NST Global, LLC v. Sig Sauer Inc.

UNITED STATES DISTRICT COURT
FOR THE DISTRICT OF NEW HAMPSHIRE
NST Global, LLC, d/b/a SB Tactical
v. 	Case No. 1:19-cv-792-PB
Opinion No. 2026 DNH 053
SIG Sauer Inc.
MEMORANDUM AND ORDER
NST Global, LLC filed this patent-infringement action, alleging that
Sig Sauer Inc.’s pivoting contour brace (“PCB”) infringes two of its patents:
U.S. Patent No. 8,869,444 (“the ’444 Patent”) and U.S. Patent No. 9,354,021
(“the ’021 Patent). In a previous order, I construed eight disputed patent
terms on which NST’s infringement claims are based. Doc. 106.
The parties then agreed to post-claim construction discovery limited to
liability issues and exchanged final infringement contentions and final
invalidity contentions pursuant to New Hampshire Supplemental Patent
Rules (“SPR”) 7.1(a) and (b). Doc. 109 at 1. Following those exchanges, Sig
Sauer moved for summary judgment. Doc. 114. It argues that its accused
products do not infringe any of the asserted patent claims, either literally or
under the doctrine of equivalents. Doc. 114-1.
Case 1:19-cv-00792-PB Document 129 Filed 05/05/26 Page 1 of 35

2
I. BACKGROUND
A. 	The Patents
The ’444 Patent and the ’021 Patent disclose “a forearm-gripping
stabilizing attachment for a handgun that secures the rearward end of [a]
handgun frame and engages a user’s forearm.” ’444 Patent col. 1 ll. 16-20.
The stabilizing attachment is designed to aid a handgun user in steadying a
gun while firing, especially when the user shoots using only one hand. ’444
Patent col. 1 ll. 13-17; ’021 Patent col. 1 ll. 16-20.
The stabilizing attachment includes “a body having a front end, a rear
end, an upper portion [and] a lower portion.” ’444 Patent col. 6 ll. 3-5, ’021
Patent col. 2 ll. 2-4. The body also includes “a passage longitudinally
extending within said upper portion and at least through the front end of said
body, the support structure of the handgun being telescopically receivable by
said passage.” ’444 Patent col. 1 ll. 53-57; ’021 Patent col. 1 ll. 55-60. One
embodiment of the ’444 Patent shows a side elevation view of how the
support structure of a handgun (62) is “telescopically receivable” within the
passage (24) of the body (14) of the forearm-gripping stabilizing attachment
(10) at Figure 7. ’444 Patent (fig. 7). Figure 7 is reproduced below.1
1 	An identical drawing is included in the ’021 Patent as Figure 7. ’021
Patent (fig. 7).
Case 1:19-cv-00792-PB Document 129 Filed 05/05/26 Page 2 of 35

3
Id.
The ’444 Patent also claims that the lower portion of the stabilizing
attachment’s body is “bifurcated so as to define a pair of spaced flaps” such
that a user’s forearm can be received between those two flaps. ’444 Patent col.
6 ll. 8-11. One embodiment of the ’444 Patent shows both a side (fig. 1) and
rear (fig. 2) view of how the lower portion of the “body” (10) bifurcates into a
pair of spaced flaps (22 and 32) that wrap around a user’s forearm (34).
’444 Patent (figs. 1, 2).
Case 1:19-cv-00792-PB Document 129 Filed 05/05/26 Page 3 of 35

4
B. 	Procedural Background
NST filed its ’444 and ’021 Patents in 2012 and 2014, respectively.
Doc. 97 at 7. Shortly thereafter, Sig Sauer became the exclusive distributor
and licensee of NST’s forearm-stabilizing attachment. Id. But in 2018, NST
discovered that Sig Sauer had developed its own stabilizing attachment for a
handgun, the PCB. Id. NST filed suit against Sig Sauer for direct
infringement of the patents, as well as induced and contributory
infringement of the ’444 Patent. Doc. 1 at 9-12. The PCB and Sig Sauer’s
associated products, all of which incorporate the PCB, are the “accused
products” in the present action. 2
About a year after NST filed its infringement action, Sig Sauer brought
two petitions for inter partes review before the Patent and Trademark
Appeals Board (“PTAB”). Doc. 68-3; Doc. 68-4. After the PTAB resolved the
petitions, NST’s only remaining claims are for infringement of claims 2, 11,
and 12 of the ’444 Patent, all three of which depend on claims 1 and 10 of the
’444 Patent, and claim 2 of the ’021 Patent, which depends on claim 1 of the
2 	In its complaint and revised final infringement contentions, NST
includes claim charts for seven distinct “accused products.” Each of these
seven incorporate the PCB, and NST only contends that the PCB component
of each accused product is infringing. NST does not contend that any other
component of the accused products infringes the ’444 or ’021 Patents. I thus
only discuss infringement by the PCB.
Case 1:19-cv-00792-PB Document 129 Filed 05/05/26 Page 4 of 35

5
’021 Patent. Doc. 96 at 8. NST still contends that the accused products
directly infringe the remaining claims of the ’444 and ’021 Patents under 35
U.S.C. § 271(a). Doc. 114-8 at 4. It also asserts that the PCB infringes the
’444 Patent by induced infringement under 35 U.S.C. § 271(b), contributory
infringement under 35 U.S.C. § 271(c), and infringement through exportation
under 35 U.S.C. § 271(f). Id. at 4-5.
The parties disputed the proper construction of eight terms contained
within the remaining claims. Doc. 106 at 2. I reproduce those claims and
their disputed terms (underlined) below.
Claim 1 of the ’444 Patent
What is claimed is:
1. A forearm-gripping stabilizing attachment for a handgun, the handgun
having a support structure extending rearwardly from the rear end of the
handgun, the forearm-gripping stabilizing attachment, comprising:
a body having a front end, a rear end, an upper portion, a lower portion,
and a passage longitudinally extending within said upper portion and
at least through said front end of said body, the support structure of the
handgun being telescopically receivable by said passage;
said lower portion being bifurcated so as to define a pair of spaced flaps
between which a user’s forearm is received when securing the
stabilizing attachment to the user’s forearm; and
a strap connected to said body, said strap securing said spaced flaps to
retain the user’s forearm between said spaced flaps when the
stabilizing attachment is secured to a user’s forearm.
’444 Patent col. 5 ll. 65-67, col. 6 ll. 1-2.
Claim 2 of the ’444 Patent
2. The forearm-gripping stabilizing attachment of claim 1, wherein said
spaced flaps are constructed of an elastomeric material and at least partially
Case 1:19-cv-00792-PB Document 129 Filed 05/05/26 Page 5 of 35

6
conform to and grip a user’s forearm when the user’s forearm is disposed
between said spaced flaps.
Id. col. 6 ll. 17-21.
Claim 10 of the ’444 Patent
10. A forearm-gripping stabilizing attachment for a handgun, the handgun
having a support structure extending rearwardly from the rear end of the
handgun, the forearm-gripping stabilizing attachment, comprising:
a body having a passage longitudinally extending therein and at least
through a front end of said body, the support structure of the handgun
being telescopically receivable by said passage;
said body defining a space within which a user’s forearm is removably
receivable;
a strap connected to said body, said strap preventing withdrawal of a
user’s forearm from said space when the forearm gripping stabilizing
attachment is secured to the user’s forearm; and
wherein said body is bifurcated and defines a pair of spaced flaps, said
pair of spaced flaps is defining said space within which the user’s
forearm is removably receivable.
Id. col. 6 ll. 54-67, col. 7 ll. 1-3.
Claim 11 of the ’444 Patent
11. The forearm-gripping stabilizing attachment of claim 10, wherein said
pair of spaced flaps are constructed of an elastomeric material.
Id. col. 7 ll. 4-6.
Claim 12 of the ’444 Patent
12. The forearm-gripping stabilizing attachment of claim 11, wherein said
pair of spaced flaps at least partially conform to a user’s forearm when the
user’s forearm is disposed between said pair of space flaps.
Id. col. 7 ll. 7-10.
Case 1:19-cv-00792-PB Document 129 Filed 05/05/26 Page 6 of 35

7
Claim 1 of the ’021 Patent
What is claimed is:
1. A forearm-gripping stabilizing attachment for a handgun, the handgun
having a support structure extending rearwardly from the rear end of the
handgun, the forearm-gripping stabilizing attachment, comprising:
a body having a front end, a rear end, an upper portion, a lower portion,
and a passage longitudinally extending within said upper portion and
at least through said front end of said body, the support structure of the
handgun being telescopically receivable by said passage;
said lower portion having at least one flap extending from said upper
portion;
a strap connected to said body, said strap securing said at least one flap to
a user’s forearm when the stabilizing attachment is secured to a user’s
forearm; and
wherein said passage extends entirely through said body between said
front end and said rear end of said body.
’021 Patent col. 6 ll. 11-15.
Claim 2 of the ’021 Patent
2. The forearm-gripping stabilizing attachment of claim 1, wherein said at
least one flap is constructed of an elastomeric material.
Id. col. 6 ll. 28-30.
In my claim construction order, I construed the disputed terms as
follows:
[T]he preamble is limiting [to the extent of “the handgun having
a support structure extending rearwardly from the rear end of the
handgun”];
“support structure” is a means-plus-function term where the
function is “being telescopically receivable” and the corresponding
structures are “a buffer tube” or “tubular member” and their
equivalents;
Case 1:19-cv-00792-PB Document 129 Filed 05/05/26 Page 7 of 35

8
“[support structure] of the handgun” is accorded its plain and
ordinary meaning, including both integral support structures and
support structures attached via a bracket;
“telescopically 	receivable 	by 	said 	passage” 	means
“removably insertable within said passage”;
“body” is accorded its plain and ordinary meaning;
“bifurcated so as to define a pair of spaced flaps” means
“divided or separated so as to define a pair of spaced flaps”;
“said lower portion having at least one flap extending from
said upper portion” is accorded its plain and ordinary meaning;
“elastomeric material” means “made of an elastomer.”
Doc. 106 at 38-39 (citation modified) (emphasis added).
Following claim construction, the parties assented to a joint discovery
plan and exchanged final infringement contentions and final invalidity
contentions pursuant to SPR 7.1(a) and (b). Doc. 109 at 1. After discovery was
completed, Sig Sauer moved for summary judgment. Doc. 114.
II. STANDARD OF REVIEW
Summary judgment is appropriate when the record reveals “no genuine
dispute as to any material fact and the movant is entitled to judgment as a
matter of law.” Fed. R. Civ. P. 56(a); Tang v. Citizens Bank, N.A., 821 F.3d
206, 215 (1st Cir. 2016). In this context, a “material fact” is one that has the
“potential to affect the outcome of the suit.” Cherkaoui v. City of Quincy, 877
F.3d 14, 23 (1st Cir. 2017) (quoting Sánchez v. Alvarado, 101 F.3d 223, 227
(1st Cir. 1996)). A “genuine dispute” exists if a factfinder could resolve the
Case 1:19-cv-00792-PB Document 129 Filed 05/05/26 Page 8 of 35

9
disputed fact in the nonmovant’s favor. Ellis v. Fid. Mgmt. Tr. Co., 883 F.3d
1, 7 (1st Cir. 2018).
The movant bears the initial burden of presenting evidence that “it
believes demonstrate[s] the absence of a genuine issue of material fact.”
Celotex Corp. v. Catrett, 477 U.S. 317, 323 (1986); accord Irobe v. U.S. Dep’t
of Agric., 890 F.3d 371, 377 (1st Cir. 2018). Once the movant has properly
presented such evidence, the burden shifts to the nonmovant to designate
“specific facts showing that there is a genuine issue for trial,” Celotex, 477
U.S. at 324, and to “demonstrate that a trier of fact could reasonably resolve
that issue in [its] favor,” Irobe, 890 F.3d at 377 (alteration in original)
(quoting Borges ex rel. S.M.B.W. v. Serrano-Isern, 605 F.3d 1, 5 (1st Cir.
2010)). If the nonmovant fails to adduce such evidence on which a reasonable
factfinder could base a favorable verdict, the motion must be granted.
Celotex, 477 U.S. at 324. In considering the evidence, I must draw all
reasonable inferences in the nonmoving party’s favor. Theriault v. Genesis
HealthCare LLC, 890 F.3d 342, 348 (1st Cir. 2018).
Case 1:19-cv-00792-PB Document 129 Filed 05/05/26 Page 9 of 35

10
III. ANALYSIS
Sig Sauer challenges NST’s infringement claims on three grounds.3
First, it contends that the PCB does not literally infringe either patent
because it does not have a support structure that is “telescopically receivable”
by the passage within its body. Sig Sauer next claims that NST forfeited its
alternative argument that the “telescopically receivable” claim limitation is
satisfied for both patents under the doctrine of equivalents because NST
failed to properly disclose that theory in its final invalidity contentions.
Finally, Sig Sauer asserts that the PCB does not infringe the ’444 Patent
because the spaced flaps in the lower portion of the PCB’s body are not
“bifurcated.” I address each argument in turn.
A. 	“Telescopically Receivable”—Literal Infringement
The parties first disagree over whether the “telescopically receivable”
claim limitation is literally present in the PCB. NST supports its contention
that the limitation is found in the PCB with two sets of diagrams in its final
infringement contentions that depict the PCB from different vantage points.
3 	To the extent Sig Sauer challenges NST’s claims of induced and
contributory infringement, it does so only in a footnote, contending that these
“claims fail for the same reason as [its direct infringement claims], since
there can be no indirect infringement without direct infringement.” Doc. 114-
1 at 13 n. 6. Sig Sauer does not challenge NST’s claims under 35 U.S.C. §
271(f). Because the parties do not brief these claims in more detail, I do not
analyze them separately.
Case 1:19-cv-00792-PB Document 129 Filed 05/05/26 Page 10 of 35

11
The first two diagrams show a “passage (I) longitudinally extending within
said upper portion (G) at least through the front end (E) of said body (D).”
Doc. 114-8 at 11.
Id. NST then points to two additional diagrams to show what it claims is “the
support structure (C) of the handgun (B) being telescopically receivable by
said passage (I).” Id. at 12.
Case 1:19-cv-00792-PB Document 129 Filed 05/05/26 Page 11 of 35

12
Id.
Sig Sauer responds by focusing on my construction that “telescopically
receivable” means “removably insertable within said passage.” In its view, a
handgun’s support structure cannot be “removably insertable” within the
passage of the PCB’s body because the support structure is attached to the
body by a washer, screw, and fastening cap. As a result, Sig Sauer argues,
the handgun’s support structure cannot be made removable from the PCB’s
passage without removing the cap and loosening the screw, a modification
that Sig Sauer claims prevents the structure from being removably
insertable.
NST replies by arguing that the “telescopically receivable” element is
present in the PCB because: (1) the limitation is cast in terms of capability;
(2) the PCB has that capability; and (3) the capability is enabled by removing
the fastening cap and loosening the screw that attaches the support structure
to the PCB’s body by hand without otherwise altering the device.
Case 1:19-cv-00792-PB Document 129 Filed 05/05/26 Page 12 of 35

13
To resolve this dispute, I first review the legal standard that
determines the issue and then assess the evidence NST identifies to support
its position.
1. 	Legal Standard
The Federal Circuit has explained on multiple occasions how a court
should address a claim that an accused device infringes an opponent’s patent
because of a latent capability. On the one hand, it has repeatedly rejected the
notion that “infringement may be based upon a finding that an accused
product is merely capable of being modified in a manner that infringes the
claims of a patent.” Fantasy Sports Props., Inc. v. Sportsline.com, Inc., 287
F.3d 1108, 1117-18 (Fed. Cir. 2002); see also INVT SPE LLC v. Int’l Trade
Comm’n, 46 F.4th 1361, 1376 (Fed. Cir. 2022); Telmac Cellular Corp. v. Topp
Telecom, Inc., 247 F.3d 1316, 1330 (Fed. Cir. 2001). On the other hand, the
court has recognized that where a claim term recites a capability, “an accused
device may be found to infringe if it is reasonably capable of satisfying the
claim limitations, even though it may also be capable of non-infringing modes
of operation.” Hilgraeve Corp. v. Symantec Corp. 265 F.3d 1336, 1343 (Fed.
Cir. 2001); see also Intel Corp. v. U.S. Int’l Trade Comm’n, 946 F.2d 821, 832
(Fed. Cir. 1991); Fantasy Sports, 287 F.3d at 1117-18; Finjan, Inc. v. Secure
Computing Corp., 626 F.3d 1197, 1204-05 (Fed. Cir. 2010). What matters in
such cases is whether the accused device is reasonably capable of satisfying
Case 1:19-cv-00792-PB Document 129 Filed 05/05/26 Page 13 of 35

14
the claim limitation without significant modification. INVT, 46 F.4th at 1376;
ParkerVision, Inc. v. Qualcomm Inc., 903 F.3d 1354, 1362 (Fed. Cir. 2018);
Ericsson, Inc. v. D-Link Sys., Inc., 773 F.3d 1201, 1217 (Fed. Cir. 2014); VLSI
Tech. LLC v. Intel Corp., No. 24-1772, slip op. at 8 (Fed. Cir. Apr. 14, 2026).
Without distinguishing these two lines of authority, Sig Sauer argues
that the result in this case is dictated by the Federal Circuit’s decision in
High Tech Medical Instrumentation, Inc. v. New Image Industries, Inc., 49
F.3d 1551, 1555 (Fed. Cir. 1995). I disagree. As I explain in detail below,
High Tech is inapplicable here because the claim limitation at issue in that
case was a structural limitation, whereas the “telescopically receivable”
limitation recites a capability rather than a structure. Accordingly, the test
for determining whether the limitation reads on the PCB asks whether the
PCB is reasonably capable of performing the claim limitation without
significant modification.
High Tech examined whether the fact that a product could be modified
for use in an infringing matter is enough to find literal infringement. 49 F.3d
at 1555. There, the claim was directed at a dental endoscope, “comprising a
body member and a camera disposed in the body member, with the camera
‘being rotatably coupled to said body member.’” Revolution Eyewear, Inc. v.
Aspex Eyewear, Inc., 563 F.3d 1358, 1369 (Fed. Cir. 2009) (citing High Tech,
49 F.3d at 1552). Users had to loosen a set of screws in order for the accused
Case 1:19-cv-00792-PB Document 129 Filed 05/05/26 Page 14 of 35

15
device to be “rotatably coupled to the body member" and thus meet the claim
limitation. High Tech, 49 F.3d at 1555-56. The Federal Circuit held that
showing that the accused device could be modified to meet the claim
limitation was insufficient, on its own, to prove infringement. Id. The court
explained that “a device does not infringe simply because it is possible to
alter it in a way that would satisfy all the limitations of a patent claim.” Id.
at 1555. Accordingly, it reversed the district court’s decision to grant the
plaintiff’s request for a preliminary injunction. Id. at 1558.
In reaching this conclusion, the court took pains to distinguish Intel,
the seminal case that deals with capability claiming. Id. at 1555-56. In Intel,
the patent disclosed a claim for “programmable selection means for selecting
alternative addressing modes.” Intel, 946 F.2d at 831. There, the court held
that “[b]ecause the language of claim 1 refers to ‘programmable selection
means’ . . . the accused device, to be infringing, need only be capable of
operating in the page mode,” adding that “actual page mode operation in the
accused device is not required.” Id. at 832.
More recently, in Revolution Eyewear, the court expressly
distinguished High Tech from cases dealing with capability claims by noting
that “the claim in High Tech requires a structure: a camera ‘rotatably
coupled’ to a body member. In contrast, [the claim at issue] only requires a
capacity to perform a function: ‘capable of engaging’ magnetic members.” 563
Case 1:19-cv-00792-PB Document 129 Filed 05/05/26 Page 15 of 35

16
F.3d at 1369. When read together, these cases leave no doubt that High Tech
does not control when assessing claims drawn to capability.
In the case before me, I agree with NST that the “telescopically
receivable” claim limitation is drawn to capability. Like the claim limitation
at issue in Intel, which involved a “programmable selection means,” Intel,
946 F.2d at 832, the limitation at issue here requires that the support
structure be “telescopically receivable” by the passage in the body of the
device. Both limitations are thus drawn to capability. See Fogg Filler Co. v.
Closure Sys. Int’l Inc., 454 F. Supp. 3d 693, 699-700 (W.D. Mich. 2020);
(applying Intel, not High Tech, where claim limitation required product to be
“rotatable” and “translatable” (emphasis added)); cf. Cross Med. Prods., Inc.
v. Medtronic Sofamore Danek, Inc., 424 F.3d 1293, 1311 (Fed. Cir. 2005)
(applying High Tech, not Intel, where “the claim does not require that the
interface be merely ‘capable’ of contacting bone” but rather “the claim has a
structural limitation that the anchor seat be in contact with bone”). And
because the limitation is drawn to capability, what matters in determining
infringement is whether the handgun’s support structure is reasonably
capable of being telescopically receivable within the passage of the PCB
without significant alteration.
Case 1:19-cv-00792-PB Document 129 Filed 05/05/26 Page 16 of 35

17
2. 	Evidence
Having determined that this issue must be analyzed using the
“reasonably capable” standard, I assess the evidence in the light most
favorable to NST to determine whether a reasonable jury could conclude that
the standard has been met. To begin with, as NST points out, “[d]irect
infringement has no intent element and for an ‘accused device to be
infringing, it need only be capable of operating’ in the infringing manner.”
Sorrell Holdings, LLC v. Infinity Headwear & Apparel, LLC, 2024 WL
413432, at * 3 (Fed. Cir. Feb. 5, 2024) (quoting Intel, 946 F.2d at 832)
(citation modified). Further, it is indisputable that the support structure of
the handgun is capable of being removed from the passage in the body of the
PCB simply by removing the fastening cap and loosening the thumbscrew
that attaches the support structure to the PCB’s body. Thus, the issue to be
resolved is whether the PCB must be significantly modified to enable this
latent capacity.
NST points to several different types of evidence to support its
contention that this issue must be resolved by a jury. First, NST identifies a
statement by Sig Sauer’s product manager that the PCB’s brace flaps “must
be removable with hand tools throughout threshold lifespan.” Doc. 116-1 at 1
(SEALED). It introduces this evidence to prove that Sig Sauer itself
acknowledges the “telescopically receivable” nature of the PCB.
Case 1:19-cv-00792-PB Document 129 Filed 05/05/26 Page 17 of 35

18
NST next introduces evidence showing that the PCB’s brace flaps can
be, and actually have been, removed from the handgun’s support structure by
users. NST’s expert reported he could “easily remove the brace flap portions
[of the accused product] by hand, using components already present on the
Accused Products.” Doc. 115 at 19. He performed this removal at a gun shop
“by loosening the rear thumb screw by hand with no tools,” showing that the
support structure of the handgun is “removable” from the PCB as assembled
and sold. Doc. 115-8 at 29.
NST bolsters its evidence of removability by pointing to “several
aftermarket products that exist to replace the spinning rubber [brace] flaps
on the Sig PCB with a non-spinning tailhook.” Id. at 30. The informational
website for one of these products instructs users to “remove the factory SIG
brace end (Simply unscrew it)” before replacing it with the aftermarket
product. Id. at 32. NST additionally references a YouTube video in which the
video creator removes a PCB from the support structure of a handgun and
replaces it with an aftermarket product. Doc. 115 at 7-8. It notes that Sig
Sauer incorrectly presents this video as evidence that “destructive[]
dismantling” of the PCB is necessary to remove it from the support structure
of the handgun; NST argues to the contrary that the video shows
removability without proof of destructive dismantling, as it shows a user
removing the brace flaps but does not necessarily show those flaps being
Case 1:19-cv-00792-PB Document 129 Filed 05/05/26 Page 18 of 35

19
destroyed. Id. at 8. At oral argument, NST likewise referenced several videos
where “the actual brace itself is removed from the back piece of the
cap . . . and then another product is placed on the back of the support
structure.” Doc. 110 at 9-10. NST contends that the existence of these
aftermarket products, which instruct users to “unscrew” the body of the PCB,
and the evidence of users removing the PCB to install said aftermarket
products “further support[] the removability of the PCB flap portion.” Doc.
115-8 at 32.
Finally, to circumstantially show removability, NST provides evidence
of Sig Sauer’s design decisions. It argues that Sig Sauer elected to employ
certain design elements for the purpose of enabling removal of the PCB’s
body from the support structure. First, NST points to the fact that Sig Sauer
“pair[ed] the knurled knob with a screw to create a functional thumb screw”
at the rear end of the PCB to enable removability. Doc. 115 at 19. Moreover,
NST notes that Sig Sauer “omit[ed] [a] thread locker” to secure that
thumbscrew, id., arguing that this omission provides further evidence of “the
intended removability of the thumb screw,” Doc. 115-8 at 30. And NST’s
expert indicates that Sig Sauer’s handguns “are designed for modularity and
customization,” and thus “designing the brace body section [of the PCB] to be
removable with a thumb-screw knob demonstrates design intent for
modularity.” Id. at 32-33.
Case 1:19-cv-00792-PB Document 129 Filed 05/05/26 Page 19 of 35

20
Turning to insertability, NST argues that the “effortless removal”
process of the PCB’s brace flaps from the support structure “preserv[es] the
structural integrity of the brace flaps which can be inserted once again
resulting in a fully operational Accused Product.” Doc. 115 at 20-21. Because
removing the brace flaps of a PCB does not alter the product’s structural
integrity, NST argues that “[t]he brace flap portions can be put back on the
support structure (support structure inserted within the passage) and the
PCB is fully functional.” Id. at 11 (citing Doc. 115-8 at 29); see also id. at 22
(“The Accused Products is not destroyed even with the third-party
[aftermarket] product replacement given that the replacement product works
on the Accused Products, and the brace flap portions can be placed back on
the Accused Products.”).
When this evidence is viewed in the light most favorable to NST, it is
sufficient to permit a reasonable jury to conclude that the actions required to
remove the PCB’s brace flaps from the support structure of the handgun
merely enable a latent capacity that the manufacturer intended the device to
have. According to NST’s evidence, enabling this latent capacity only requires
actions that are reversible, nondestructive, and do not require specialized
tools. That evidence is sufficient to raise a triable issue as to whether the
PCB is reasonably capable of removable insertability without significant
modification.
Case 1:19-cv-00792-PB Document 129 Filed 05/05/26 Page 20 of 35

21
In response to NST’s evidence, Sig Sauer attempts to show in multiple
ways that the handgun’s support structure is not “removably insertable”
within the passage of the PCB. First, Sig Sauer attempts to undermine NST’s
evidence on “insertability.” However, its efforts on this score are no more
than a passing reference. Sig Sauer’s only argument regarding insertability is
embedded within its response to NST’s Statement of Material Facts in
Dispute. In response to NST’s statement that “[t]he brace flap portions can be
put back on the support structure (support structure inserted within the
passage) and the PCB is fully functional,” Sig Sauer states:
For the purposes of its SJ Motion, SIG does not dispute [Plaintiff’s
Statement of Facts] 25-26 insofar as it may be technically possible
to disassemble the PCB and reassemble the device. However,
NST’s citation does not show reassembly. Therefore, NST adduces
no evidence that any customer or third-party disassembled and
removed the arms/flaps from the SIG PCB for any reason other
than to remove them permanently and discard them . . . .
Doc. 121 at 8. Sig Sauer makes no other substantive argument regarding
insertability in either its opening brief or in its reply to NST’s brief in
opposition. As the First Circuit has held, “[t]he district court is free to
disregard arguments not adequately developed.” Higgins v. New Balance
Athletic Shoe, Inc., 194 F.3d 252, 260 (1st Cir. 1999). Because Sig Sauer does
not fully develop an argument regarding insertability, I cannot assess the
merits of its argument.
Case 1:19-cv-00792-PB Document 129 Filed 05/05/26 Page 21 of 35

22
More broadly, Sig Sauer makes several attempts to undermine NST’s
evidence that the support structure is removably insertable within the
passage of the PCB, none of which are persuasive. In its only substantive
effort, Sig Sauer argues that because NST’s expert was only able to remove
the brace flaps after receiving confidential information regarding the accused
product’s design, his opinion does not represent a customer’s ability to
remove the flaps by hand.4 Sig Sauer argues that under Provisur
Technologies, Inc. v. Weber, Inc., this kind of expert testimony cannot be used
to prove infringement. See 119 F.4th 948 (Fed. Cir. 2024). Provisur is
distinguishable from the current case, however. In Provisur, the expert was
only able to operate the accused product in an infringing manner when
provided “access to screens that [the accused product’s] customers do not”
have access to. Id. at 954. The court held that because “customers do not have
access to the screens Provisur contends are necessary for the [accused
product] to operate [in an infringing manner],” the case was “not an
infringement scenario where customers can simply activate the infringing
configuration.” Id. at 954-55. Unlike the expert in Provisur, NST’s expert did
4 	Sig Sauer additionally attempts to discredit NST’s expert by arguing
that the expert’s report cannot be used as evidence of Sig Sauer’s intent for
the accused products to be used in an infringing manner. However, these
arguments are immaterial under Intel and the “reasonably capable”
standard, which does not require proof of intent.
Case 1:19-cv-00792-PB Document 129 Filed 05/05/26 Page 22 of 35

23
not require any tools, technologies, or devices unavailable to customers to
remove the brace flaps of the PCB from the handgun’s support structure; he
simply unscrewed the flaps using the thumbscrew that exists within each
accused product as assembled and sold. Therefore, NST’s expert was merely
“activating means that are already present in the underlying [product],” and
his testimony raises a triable issue of fact as to whether a customer could
likewise remove the PCB’s brace flaps from the handgun’s support structure
using the accused product’s thumbscrew. Fantasy Sports, 287 F.3d at 1118
(citation modified). Provisur is thus inapposite and does not undermine the
testimony of NST’s expert on removability.5
Based on the foregoing, I conclude that NST has identified sufficient
evidence to raise a genuine dispute of material fact as to whether a
5 	Sig Sauer also makes a procedural argument that NST impermissibly
“sand-bagg[ed]” Sig Sauer by introducing new infringement theories on
removability through its expert report. Doc. 121 at 22. This argument is
unavailing. SPR 7.1(a) requires the party asserting infringement to serve its
final infringement contentions, including “the party’s final statement of all
contentions required by SPR 5.1(a),” and NST did so here. See Doc. 114-8.
The rules do not require production of evidentiary support for the contentions
at the contention stage. NST’s claim chart, produced in tandem with its final
infringement contentions, sufficiently identifies how the accused products
meet the “telescopically receivable” claim limitation. See Doc. 114-8 at 12-13.
The final infringement contentions do not “identify additional accused
products or processes not set out in the Preliminary Infringement
Contentions,” so no amendment or further explanation is necessary. See SPR
7.1(a)(2).
Case 1:19-cv-00792-PB Document 129 Filed 05/05/26 Page 23 of 35

24
handgun’s support structure is “removably insertable” in the passage of the
PCB without significant alteration. Moreover, Sig Sauer fails in each of its
attempts to undermine NST’s evidence on this matter. Accordingly, I deny
Sig Sauer’s motion for summary judgment on this ground.
B. 	“Telescopically Receivable”—Doctrine of Equivalents
Sig Sauer next argues that NST forfeited its right to assert that the
“telescopically receivable” claim limitation has been met under the doctrine of
equivalents because it failed to disclose its theory in the manner required by
the court’s local rules.
This district’s SPRs require a party claiming infringement to serve both
“Preliminary Infringement Contentions,” SPR 5.1(a), and “Final
Infringement Contentions,” SPR 7.1(a). Preliminary infringement contentions
must “include an infringement claim chart for each accused product.” SPR
5.1(a). That claim chart must disclose, among other things, “[w]hether each
limitation of each asserted claim is alleged to be literally present or present
under the doctrine of equivalents in the Accused Instrumentality.” SPR
5.1(a)(1)(D). Additionally, no more than twenty-one days after the court
issues its claim construction order, “any party asserting infringement must
serve on all parties its ‘Final Infringement Contentions,’ which shall include
the party’s final statement of all contentions required by SPR 5.1(a).” SPR
7.1(a)(1). Thus, the local rules require a party claiming infringement to state
Case 1:19-cv-00792-PB Document 129 Filed 05/05/26 Page 24 of 35

25
whether a claim limitation is met under the doctrine of equivalents in both
its preliminary infringement contentions and final infringement contentions.
NST served timely preliminary6 and final infringement contentions in
accordance with the SPRs, but its disclosures made no mention of the
doctrine of equivalents. After NST made its final infringement contentions
and Sig Sauer its final invalidity contentions, the parties submitted a joint
proposed discovery plan (which I later approved) that authorized NST to
serve a second set of final infringement contentions after the completion of
discovery. Doc. 109.
NST served its revised final infringement contentions on Sig Sauer
pursuant to that approved plan on February 20, 2025. Doc. 114-8 at 8. It was
in those revised final infringement contentions that NST first mentioned the
doctrine of equivalents by stating as follows:
To the extent any element of the Claims-in-Suit are not literally
met, 	NST 	contends 	that 	such 	element 	is 	satisfied 	under 	the
doctrine of equivalents. Specifically, the Accused Products perform
substantially the same function, in substantially the same way, to
achieve substantially the same result as required by the claim
elements of the support structure being telescopically receivable in
the passage. For example, the support structure of the Accused
Product is telescopically receivable in the passage of the body of
6 	The docket does not contain a record of NST’s preliminary infringement
contentions, but neither party has challenged the timeliness or substantive
adequacy of those contentions. Accordingly, for the purpose of this analysis,
we assume NST’s preliminary infringement contentions were timely.
Case 1:19-cv-00792-PB Document 129 Filed 05/05/26 Page 25 of 35

26
the forearm-gripping stabilizing attachment equivalent to that of
a support structure that is removably insertable.
Id. at 3-4.
Sig Sauer focuses its challenge to NST’s revised final infringement
contentions on the content of those disclosures rather than their timing.7 In
its view, NST’s attempt to invoke the doctrine of equivalents is insufficient
because it is nothing more than a conclusory statement that the doctrine
applies without explaining “why and how” the claim element has been met
under the doctrine. Doc. 114-1 at 25. Although SPR 5.1(a)(1)(D) does not
expressly require a more detailed disclosure, I agree with other districts that
more than a conclusory statement regarding the doctrine of equivalents is
required.
In other districts that have adopted nearly identical local rules
regarding the doctrine of equivalents to those of this court, “a general
reservation of the right to assert infringement under the doctrine of
equivalents does not satisfy a plaintiff’s obligation to disclose its infringement
7 	To the extent that Sig Sauer argues that the disclosures were also
untimely, I decline to address its argument because it has not been
sufficiently developed. Nor do I address any possible argument based on the
adequacy of NST’s expert disclosures because that argument too has not been
sufficiently developed.
Case 1:19-cv-00792-PB Document 129 Filed 05/05/26 Page 26 of 35

27
analysis as required by [the local patent rules].” DNA Genotek Inc. v.
Spectrum Sols, L.L.C., 671 F. Supp. 3d 1105, 1125 (S.D. Cal. 2023). Instead,
such courts say that compliance with the local rules requires a patentee to
“provide ‘a limitation-by-limitation’ analysis as to why and how there is
infringement under the doctrine of equivalents.” Id. (citing Bell
Semiconductor, LLC v. NXP USA, Inc., 2023 WL 2342037, at *7 (S.D. Cal.
Feb. 27, 2023); see also ASUS Comput. Int’l v. Round Rock Rsch., LLC, 2014
WL 1463609, at *3 (N.D. Cal. Apr. 11, 2014) (holding that “blanket
contentions that do not sufficiently identify the DOE as the manner that the
products infringe” do not sufficiently to satisfy the local rule). NST’s revised
final infringement contentions fail to describe why and how there is
infringement under the doctrine of equivalents, and I therefore find they do
not satisfy SPR 5.1(a)(1)(D).
I am not convinced, however, that preclusion is the appropriate remedy
here. It is true that our local rules bar a party claiming infringement from
“assert[ing] at trial any infringement contentions not set out in its Final
Infringement Contentions,” SPR 7.1(a)(1). However, our local rules also allow
me to “excuse a failure to comply with any local rule whenever justice so
requires.” LR 1.3(b). This rule permits courts to conduct a more nuanced
analysis into whether a party’s failure to comply with a local rule should
result in preclusion. Given that SPR 5.1(a)(1)(D) does not expressly require a
Case 1:19-cv-00792-PB Document 129 Filed 05/05/26 Page 27 of 35

28
more detailed disclosure of a doctrine of equivalents theory and case law in
our district is silent as to the substantive requirements of that rule, I believe
that a more nuanced analysis as to why NST failed to comply with the local
rules is warranted here.
Federal Rule of Civil Procedure 37(c), which discusses appropriate
sanctions for parties who fail to make mandatory disclosures during
discovery, provides a useful analogue in assessing NST’s failure to disclose its
doctrine of equivalents theory pursuant to SPR 5.1 and 7.1. See Fed. R. Civ.
P. 37(c). Accordingly, I assess the present circumstances under its standards.
Under Rule 37(c), “[i]f a party fails to provide information or identify a
witness as required by [Rules] 26(a) or (e), the party is not allowed to use that
information . . . to supply evidence . . . at trial, unless the failure was
substantially justified or is harmless.” Fed. R. Civ. P. 37(c) (emphasis added).
Thus, while Rule 37 sets preclusion as the “baseline sanction” for failure to
disclose, preclusion is not “‘strictly required,’ and the district court retains
discretion to impose a less severe sanction.” G.K. v. Sununu, 2024 DNH 050,
2024 WL 3011178, at *4 (D.N.H. June 14, 2024) (citing Lawes v. CSA
Architects & Eng’rs LLP, 963 F.3d 72, 91 (1st Cir. 2020)).
Here, the parties have not addressed in detail whether NST’s failure to
disclose its doctrine of equivalents theory was substantially justified or
harmless. NST provides no explanation for its failure to disclose why and how
Case 1:19-cv-00792-PB Document 129 Filed 05/05/26 Page 28 of 35

29
there is infringement under doctrine of equivalents, and Sig Sauer, in turn,
has not shown how it has been harmed by NST’s insufficient disclosure. Until
the parties brief this issue in more detail, therefore, I am unable to determine
the appropriate sanction for NST’s failure to comply with SPR 5.1(a)(1)(D)
and 7.1.8
C. 	“A Body” That Is “Bifurcated”
The ’444 Patent requires “a body having . . . a lower portion . . . said
lower portion being bifurcated so as to define a pair of spaced flaps.” ’444
Patent col. 5 ll. 65-67, col. 6 ll. 1-2. In my claim-construction order, I
interpreted two phrases contained within the above limitation. First, I
determined that “body” must be accorded its “plain and ordinary meaning.”
Doc. 106 at 32. I rejected Sig Sauer’s proposed construction of the term “body”
to require a “unitary” component and instead agreed with NST that the body
can be “comprised of multiple components.” Id. at 30-31 (“Neither of these
8 	Sig Sauer also challenges the substance of NST’s doctrine of
equivalents theory. It argues that even if the Court permits NST to assert the
doctrine of equivalents as to “telescopically receivable,” any use of the
doctrine would “vitiate the claim language” in question here. Doc. 114-1 at
21-22. It argues that the PCB “can only be disassembled with tools and then
dismantled for the purposes of discarding a primary portion of the device,”
which, it contends, is “the polar opposite of the removably insertable brace of
the Patents-in-Suit.” Id. at 26. However, because Sig Sauer’s claim-vitiation
argument is premised on material facts in dispute—namely, that removing
the PCB’s brace flaps requires “destructive dismantling” and “discarding” the
device—this argument likewise fails at summary judgment.
Case 1:19-cv-00792-PB Document 129 Filed 05/05/26 Page 29 of 35

30
definitions, however, require that the body be comprised of just one
component.”). Second, I construed “bifurcated so as to define a pair of spaced
flaps” to mean “divided or separated so as to define a pair of spaced flaps.” Id.
at 33.
In its revised final infringement contentions, NST argues the accused
products meet the “bifurcated” “body” limitation described in the ’444 Patent.
It contends that the two images below, one diagram of an accused product
and one photograph of an accused product, show a “lower portion (H) [of the
body] being bifurcated so as to define a pair of spaced flaps (K) between
which a user’s forearm is received when securing the stabilizing attachment
(A) to the user’s forearm.” Doc. 114-8 at 13.
Case 1:19-cv-00792-PB Document 129 Filed 05/05/26 Page 30 of 35

31
Id.
In response to these contentions, Sig Sauer moves for summary
judgment on the ground that NST cannot prove that the accused products
have a “body” whose lower portion [is] “divided or separated so as to define a
pair of spaced flaps.” See Doc. 106 at 39. It argues that because the accused
product has “[t]wo separate bodies, each consisting of its own flap,” those two
flaps are not “a body” that is bifurcated; instead, it argues that “the body still
has to be singular in some aspect such that two flaps can form branches from
what was one part.” Doc. 114-1 at 27.
The first component of Sig Sauer’s argument is that the claim
limitation envisions “a body” in the singular, rather than the plural. Sig
Sauer cites TiVo, Inc. v. EchoStar Communications Corporation in support of
this argument. See 516 F.3d 1290 (Fed. Cir. 2008). TiVo held that although
the words “a” or “an” in a patent claim generally mean “one or more,” that
“rule does not apply when . . . the claims and written description . . . make
Case 1:19-cv-00792-PB Document 129 Filed 05/05/26 Page 31 of 35

32
clear that the singular meaning applies.” Id. at 1303. Sig Sauer argues that,
as in TiVo, the present claims as construed “require ‘branching’ from ‘a’
body,” such that when read in context, those claims “can only mean from one
part to two.” Doc. 114-1 at 29. Because the PCB’s body “is already comprised
of two separate parts,” Sig Sauer contends, there is no “bifurcation to two
flaps because they already consist of two completely separate parts.” Id.
In response, NST argues that a triable issue of fact exists over whether
an PCB’s two brace flaps constitute “a ‘body’” that is “separated or divided as
to define a pair of spaced flaps.” Doc. 115 at 29-30. It contends that Sig
Sauer’s argument on this point both ignores my claim-construction order and
misapplies TiVo to the present case. NST argues that because my claim
construction order determined that “the body can be comprised of multiple
components attached together so as to form a unitary body,” Sig Sauer’s
argument that the accused products have more than one body, rather than “a
body,” fails. Id. at 30 (citing Doc. 106 at 30 n.5). It also contends that “[i]f any
analogies can be drawn [between TiVo and this case], reading two (2)
separate components can be combined and considered unitary is consistent
with a finding under the Court’s construction of ‘a body’ and that the Accused
Products’ brace flap portions meet that limitation.” Id.
I conclude that NST has raised a triable issue of fact over whether the
accused products have “a body” whose lower portion is “divided or separated
Case 1:19-cv-00792-PB Document 129 Filed 05/05/26 Page 32 of 35

33
so as to define a pair of spaced flaps.” To start, my claim-construction order
expressly determined that a body can be “comprised of multiple components,”
Doc. 106 at 30, and Sig Sauer’s argument that two separate flaps cannot
constitute a single body thus necessarily fails. Just as “the body of a car is
generally . . . manufactured in separate pieces . . . and assembled into a
single structure,” id. at 31, a reasonable juror could find that the two
separate brace flaps here, when assembled and held together at their upper
portions using a hex bolt and thumb screw, form a single structure and thus
constitute a single “body.”
Moreover, Sig Sauer’s arguments about TiVo simply do not apply to the
PCB. TiVo does hold that “the question whether ‘a’ or ‘an’ is treated as a
singular or plural depends heavily on the context of its use” and the “general
rule does not apply when the context clearly evidences that the usage is
limited to the singular.” 516 F.3d at 1303. I also agree with Sig Sauer’s
argument that “a body” could be understood as singular in the current claim.
However, Sig Sauer strains logic when it argues that “[t]wo separate bodies,
each consisting of its own flap, is not bifurcation.” Doc. 114-1 at 27. Although
I agree that “a body” here is used in the singular, that does not mean there is
no bifurcation simply because the body is comprised of two separate pieces
joined together. On the contrary, a reasonable juror could find that the body
is composed of two flaps that “divide or separate so as to define a pair of
Case 1:19-cv-00792-PB Document 129 Filed 05/05/26 Page 33 of 35

34
spaced flaps” when they are axially rotated from their connected upper
portion.
This claim limitation must be assessed in two separate steps: (1) is
there “a body” in the accused products; and (2) if so, does that body’s lower
portion “divide or separate so as to define a pair of spaced flaps”? On the first
question, I already determined that “a body” could consist of more than one
piece, and thus a reasonable juror could find that the two brace flaps, when
assembled together in a PCB, constitute “a body.” On the second question, a
reasonable juror could also find that when that the “body” hinges open, the
lower portion of the body “divide[s] or separate[s] so as to define a pair of
spaced flaps.” NST contends that the “upper portion” of the body is the
portion of the PCB where the two flaps are joined together to form a
“passage,” whereas the “lower portion” of the body consists of the rotatable
portions of the brace flaps that are “bifurcated” to receive a user’s forearm.
Doc. 115-8 at 33. Under this construction, a reasonable juror could find that
both parts of the claim limitation are satisfied by the PCB. Therefore, I
conclude that NST presents a triable issue of fact over whether the PCB has
a “body” that’s lower portion is “bifurcated so as to define a pair of spaced
flaps.”
Case 1:19-cv-00792-PB Document 129 Filed 05/05/26 Page 34 of 35

35
IV. CONCLUSION
Based on the foregoing, I determine that NST raises genuine issues of
material fact as to literal infringement on the “telescopically receivable” and
“bifurcated” “body” claim limitations of the Patents. Moreover, although I
find that NST has not substantively complied with SPR 5.1 and 7.1 in
disclosing its doctrine of equivalents theory, I cannot determine at present
whether preclusion is the appropriate sanction, nor can I grant summary
judgment on this claim. Accordingly, I deny Sig Sauer’s motion for summary
judgment as to infringement of the “telescopically receivable” claim
limitation, both literally and under the doctrine of equivalents, and literal
infringement of the “bifurcated” “body” claim limitation. Doc. 114.
SO ORDERED.
/s/ Paul J. Barbadoro
Paul J. Barbadoro
United States District Judge
May 5, 2026
cc: 	Counsel of Record
Case 1:19-cv-00792-PB Document 129 Filed 05/05/26 Page 35 of 35