NOTE: This disposition is nonprecedential.

United States Court of Appeals 

for the Federal Circuit ______________________ 

FENF, LLC,

Plaintiff-Appellee,

v.

SMARTTHINGZ, INC.,

Defendant-Appellant.

______________________ 

2014-1490

______________________ 

Appeal from the United States District Court for the 

Eastern District of Michigan in No. 2:12-cv-14770-PJDMKM, Judge Patrick J. Duggan.

______________________ 

Decided: February 6, 2015

______________________ 

 RICHARD W. HOFFMANN, Reising Ethington P.C., of 

Troy, Michigan, argued for plaintiff-appellee. With him 

on the brief was MICHAEL J. DRUZINSKI. 

 CHRISTOPHER K. HU, Blank Rome LLP, of New York, 

New York, argued for defendant-appellant.

______________________ 

Before LOURIE, MOORE, and O’MALLEY, Circuit Judges.
2 FENF, LLC v. SMARTTHINGZ, INC. 

LOURIE, Circuit Judge. 

SmartThingz, Inc. (“SmartThingz”) appeals from the 

decisions of the United States District Court for the 

Eastern District of Michigan granting a permanent injunction against SmartThingz, and entering final judgment in favor of FenF, LLC (“FenF”). FenF, LLC v. 

SmartThingz, Inc., No. 12-cv-14770, 2014 WL 1431692 

(E.D. Mich. Apr. 14, 2014) (“Injunction Order”); J.A. 30. 

The judgment was entered in accordance with a stipulation by the parties that under the court’s construction of 

the term “separators” in FenF, LLC v. SmartThingz, Inc., 

No. 12-cv-14770, 2013 WL 3868071 (E.D. Mich. July 25, 

2013) (“Opinion”), SmartThingz’s accused product infringed the asserted claim of U.S. Patent 8,002,675 (“the 

’675 patent”) and the claim was not invalid. J.A. 30. 

Because we find that the district court erred in construing 

the term “separators” in claim 35, we vacate the district 

court’s final judgment and the permanent injunction, and 

remand for further proceedings. 

BACKGROUND

FenF owns the ’675 patent, which is directed to foot 

therapy devices for aligning, stretching, and exercising 

toes. Claims 1–34 recite, and the majority of the specification describes, foot therapy devices comprising one or 

more “posts” formed of an elastic material, to be placed

between a user’s toes in order to stretch the toes. At issue 

in this case, however, is claim 35, which reads as follows:

35. A foot-therapy and toe-aligning device, comprising:

a frame with four separators for separating a plurality of toes, wherein the frame comprises a top 

portion, a bottom portion, a front portion, and a 

back portion, with the separators connecting the 

top portion with the bottom portion;
FENF, LLC v. SMARTTHINGZ, INC. 3

wherein the separators, in combination with the 

top portion and the bottom portion, form three 

holes through the frame for insertion of a plurality of toes, wherein each hole includes an entrance 

into the back portion, an exit from the front portion, and surrounding walls connecting the entrance with the exit;

wherein the four separators include two outer 

separators and two inner separators, such that 

each of the two outer separators include an inner 

portion that forms a surrounding wall in a corresponding hole and an outer portion that does not 

operate as a surrounding wall to a hole; and

wherein at least one of the top portion and the 

bottom portion includes at least one elongated section that extends beyond the outer portion of at 

least one of the two outer separators.

’675 patent col. 19 l. 7–col. 20 l. 13 (emphasis added). 

FenF sued SmartThingz, alleging infringement of the 

’675 patent by SmartToes, a foot therapy product imported by SmartThingz. The parties narrowed the issues by

stipulating that the asserted infringement was based 

solely on claim 35, and that SmartThingz would file a 

motion for summary judgment of invalidity under § 102(b)

based on U.S. Patent 6,238,357. 

SmartThingz filed its motion for summary judgment, 

asserting that no claim construction was necessary. 

However, the district court held a claim construction 

hearing to consider two phrases containing the term

“separators.” The court construed “separators” to mean

“posts formed of an elastic material (or a material with 

elastomeric properties) such that they have the ability to 

stretch and elongate vertically and expand outwardly.” 

Opinion at *5, *7. 
4 FENF, LLC v. SMARTTHINGZ, INC. 

Drawing from the specification, the district court noted how the patent emphasizes the “important effects” of

the elastic characteristics and how the improvements over 

the prior art are premised on the use of an elastic material. Id. at *5. The court stated that the patent describes 

posts “as a particular formulation of a separator (i.e., one 

made from an elastic material)” and determined that “all 

posts are separators but not all separators are posts.” Id.

at *6. Nonetheless, the court found that the patent 

“equates” posts with separators, rather than treating 

them as two different “aspects” of the device. Id. The 

court accordingly held that “a device comprised of separators ‘formed of an elastic material’ is the only invention 

the ’675 patent covers.” Id. (emphasis added). The court 

therefore concluded that claim 35 uses the term “separators” to refer to “a specific category of separators” in the 

context of the patent as a whole. Id. at *7.

Under the district court’s construction, SmartThingz

conceded that its motion for summary judgment of invalidity must be denied, and stipulated to infringement of 

claim 35 to put the case in a posture for appeal.

FenF then moved for a permanent injunction, which

the district court granted. Injunction Order at *5. The 

court found that SmartThingz’s stipulation of infringement sufficed for FenF to demonstrate its success on the 

merits. Id. The court accordingly issued a permanent 

injunction and entered a final judgment in favor of FenF. 

J.A. 30.

SmartThingz timely appealed. We have jurisdiction 

pursuant to 28 U.S.C. § 1295(a)(1).

DISCUSSION

We review the district court’s claim construction de

novo because the intrinsic record—the claims, the specification, and the prosecution history—fully informs the 

proper construction in this case. See Teva Pharm. USA, 
FENF, LLC v. SMARTTHINGZ, INC. 5

Inc. v. Sandoz, Inc., 574 U. S. ___, 135 S. Ct. 831, 841 

(2015). The district court’s claim construction relied only 

on intrinsic evidence, not on any testimony by one of 

ordinary skill in the art about the meaning of separators

in the relevant art during the relevant time period.

The words of a claim are generally given their ordinary and customary meaning, which is the meaning that 

the term would have to a person of ordinary skill in the 

art when read in the context of the entire patent. Phillips 

v. AWH Corp., 415 F.3d 1303, 1312–13 (Fed. Cir. 2005)

(en banc) (citations and internal quotation marks omitted). “Claims must be read in view of the specification, of 

which they are a part.” Markman v. Westview Instruments, Inc., 52 F.3d 967, 979 (Fed. Cir. 1995) (en banc), 

aff’d, 517 U.S. 370 (1996). The specification is “the single 

best guide to the meaning of a disputed term.” Phillips, 

415 F.3d at 1315 (quoting Vitronics Corp. v. Conceptronic, 

Inc., 90 F.3d 1576, 1582 (Fed. Cir. 1996)). 

SmartThingz argues that “separator” did not need to 

be construed because the patent uses the ordinary meaning of “something that separates,” without a limitation of 

elasticity. SmartThingz contends that the patent differentiates between separators and posts, which the district 

court acknowledged in juxtaposition with its conclusion

that separators are posts. According to SmartThingz, 

posts in the context of the patent are a subset of separators, with a specific characteristic of elasticity. All of the 

examples cited by the district court to support its construction, SmartThingz notes, refer to the elastic characteristic of posts, not separators. SmartThingz further

asserts that the patent discloses two different embodiments: one with posts, which must be elastic and is 

claimed in claims 1–34, and one with separators, which is 

more generic and is claimed in claim 35.

FenF responds that the patent as a whole teaches 

that the separators of the invention must be elastic. The 
6 FENF, LLC v. SMARTTHINGZ, INC. 

phrase “the present invention” is repeatedly used, FenF 

asserts, to highlight the importance of the elastic nature 

of the device and its corresponding ability to conform its 

shape to the user’s toes. FenF argues that the specification clearly teaches that elasticity is a universal, functional feature for all embodiments of the invention, not 

merely a structural feature of the preferred embodiment. 

FenF contends that because posts and separators are 

related structures and have the same core function, the 

characterizations of the desired elasticity of posts in the 

specification are equally applicable to separators. Moreover, FenF argues, the specification distinguishes the 

invention as a whole over the prior art based on the 

disclosed elastic features, and thus disavows devices with 

rigid separators. 

We agree with SmartThingz that “separators” in the 

’675 patent are not necessarily formed of an elastic material. The word is not so limited in the text of the claim or 

in the context of the entire patent.

Claims 1–34 recite devices with posts, and we note 

that no one disputes that posts in the context of this 

patent must be formed of an elastic material. But nothing 

in the intrinsic record states that a separator is a post. 

Posts are not the same as separators, even if they both

serve the same function of separating toes. Claim 35 is 

the only claim that recites a device with separators. It is 

also the only independent claim that does not recite 

“post(s) formed of an elastic material.” Compare ’675 

patent col. 16 l. 31 (claim 1), id. col. 17 l. 3 (claim 9), id.

col. 18 l. 12 (claim 24), id. col. 18 l. 49 (claim 31), and id.

col. 18 l. 61 (claim 33), with id. col. 19 l. 7–col. 20 l. 13

(claim 35). The language of claim 35 itself does not limit 

the term separators to being formed of an elastic material 

or having elastic properties. The scope of the claim, 

therefore, does not appear restricted to encompassing only 

embodiments formed of an elastic material.
FENF, LLC v. SMARTTHINGZ, INC. 7

The specification also discloses certain embodiments—with posts—that must be formed of an elastic 

material, and one particular embodiment—with separators—that has no associated elastic properties. In a

specification, the phrase “the present invention” is quite 

often a keystone for interpreting a claim in light of the 

specification rather than in accordance with meanings it 

could otherwise be given. G.E. Lighting Solutions, LLC v. 

AgiLight, Inc., 750 F.3d 1304, 1309 (Fed. Cir. 2014). The 

phrase usually prefaces some circumscription of the 

meaning of certain claim language. Even though it appears throughout the specification of the ’675 patent, 

however, the phrase here appears to refer to separate 

embodiments, with language that is tracked in separate

claims. For example, in the Summary of the Invention 

section, the specification describes thirty discrete aspects

of the present invention, of which only the twenty-seventh 

aspect uses the word separator. ’675 patent col. 3 l. 13–

col. 5 l. 34. Most of these aspects are incorporated virtually verbatim throughout claims 1–34, and the twentyseventh aspect mirrors claim 35. 

Further support for this differentiation of embodiments comes from the corresponding descriptions of 

Figures 1–14, which depict various possible embodiments 

with posts, contrasted with the description of Figure 15, 

which has separators. As the district court noted, the 

Detailed Description section repeatedly emphasizes the 

importance of the posts of the invention being formed of 

an elastic or elastomeric material. See Opinion at *5. 

Those descriptions, however, are all directed to Figures 1–

14 and Claims 1–34. 

Ultimately it is the patent’s very specific description 

of Figure 15, which in turn depicts what is claimed in 

claim 35, that makes clear that separators need not be of 

an elastic or elastomeric material to fall within the 

bounds of that claim. Figure 15 is discussed starting in 

column 13, where the first and only instance of the word
8 FENF, LLC v. SMARTTHINGZ, INC. 

separator appears in the Detailed Description section. 

’675 patent col. 13 l. 59. There, the patent expressly 

states that separators may be made of various suitable 

materials, including plastic, silicone, and cork, id. col. 13 

ll. 60–62. It then goes on to explain how “an openable toe 

hole” allows for “easy insertion” of toes, id. col. 14 ll. 11–

15, and touts the advantages of openable toe holes in

“accommodation of toe movement/articulation,” id. col. 14 

ll. 44–54. The description does not state that the device

with separators shown in Figure 15 must be formed of an 

elastic or elastomeric material, has posts, or is beneficial 

over the prior art for its elastic or elastomeric properties. 

We therefore conclude that the district court erred in 

construing “separators” as narrowly as it did.

Although we have determined that the term is not as 

limited as construed by the district court, we also note for

purposes of remand that we find no indication that the 

patentee acted as his own lexicographer with regard to 

the term “separator” or disavowed any particular meaning 

of the term. Based on the intrinsic evidence, we understand the plain and ordinary meaning of “separators” in 

claim 35 in the context of the ’675 patent to be “structural 

features that can be placed between toes.” For the sake of 

clarity, we note that separators may be, but are not necessarily, formed of an elastic or elastomeric material. 

Because of the revised claim construction, we vacate

and remand for further proceedings consistent with this 

opinion. The concessions and stipulations regarding 

invalidity and infringement were based on the erroneous 

claim construction; ergo, the permanent injunction must 

also be vacated. 

CONCLUSION

We have considered the remaining arguments and 

conclude that they are without merit. For the foregoing 

reasons, we vacate the final judgment and the permanent 

injunction, and remand the case.
FENF, LLC v. SMARTTHINGZ, INC. 9

VACATED AND REMANDED

COSTS

Costs to SmartThingz.