United States Court of Appeals 

for the Federal Circuit ______________________ 

SOCLEAN, INC.,

Plaintiff-Appellee

v.

SUNSET HEALTHCARE SOLUTIONS, INC.,

Defendant-Appellant

______________________ 

2021-2311

______________________ 

Appeal from the United States District Court for the 

District of Massachusetts in No. 1:20-cv-10351-IT, Judge 

Indira Talwani.

______________________ 

Decided: November 9, 2022

______________________ 

BRENDAN COX, Laredo & Smith, LLP, Boston, MA, argued for plaintiff-appellee. Also represented by PAYAL 

SALSBURG. 

 JOHN LABBE, Marshall, Gerstein & Borun LLP, Chicago, IL, argued for defendant-appellant. Also represented 

by MARK HARRY IZRAELEWICZ, TIFFANY D. GEHRKE. 

 ______________________ 

Before NEWMAN, LOURIE, and PROST, Circuit Judges.

Case: 21-2311 Document: 41 Page: 1 Filed: 11/09/2022
2 SOCLEAN, INC. v. SUNSET HEALTHCARE SOLUTIONS, INC. 

PROST, Circuit Judge. 

Sunset Healthcare Solutions, Inc. (“Sunset”) appeals 

the U.S. District Court for the District of Massachusetts’s 

order granting preliminary injunctive relief to SoClean, 

Inc. (“SoClean”) requiring “Sunset to clearly associate its 

online marketing and sales . . . with the Sunset brand.” SoClean, Inc. v. Sunset Healthcare Sols., Inc., 554 F. Supp. 3d 

284, 308 (D. Mass. 2021). We affirm.

BACKGROUND

This appeal is a small part of a larger intellectual-property dispute between SoClean, a medical-device company 

that produces sanitizing devices for Continuous Positive 

Airway Pressure (“CPAP”) machines, and Sunset, one of its 

former distributors. As relevant here, SoClean owns 

U.S. Trademark Registration No. 6,080,195 (“the ’195 registration”) for the configuration of replacement filters for 

its sanitizing devices:

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SOCLEAN, INC. v. SUNSET HEALTHCARE SOLUTIONS, INC. 3

SoClean sued Sunset for patent infringement on February 20, 2020; it filed a second patent-infringement lawsuit about a year later; and, shortly thereafter, it amended 

the complaint in the second lawsuit to assert trademarkinfringement claims based on, among others, the ’195 registration. The district court consolidated the two cases at 

the parties’ request. 

On April 23, 2021, SoClean asked the district court to 

preliminarily enjoin Sunset from using, selling, offering for 

sale, or making in the United States filters that SoClean 

alleged infringed the ’195 registration. The district court 

granted the motion in part, concluding that SoClean was 

likely to succeed on the merits and, accordingly, was entitled to a presumption of irreparable harm. SoClean, 554 F. 

Supp. 3d at 306–07. Balancing the equities and weighing 

the public interest, the district court concluded that SoClean’s request to enjoin all sales of Sunset’s filters would 

“go[] much further than necessary” to “end any possible 

statutory violation.” Id. at 308. The district court instead 

crafted a narrow “injunction that prohibits Sunset from engaging in those practices that result in consumer confusion” and enjoined Sunset from marketing its filters “using 

images of the filter cartridge alone”; “[a]ny image, drawings, or other depictions of Sunset’s filter cartridge used for 

the purposes of promotion, marketing and/or sales shall 

prominently display the Sunset brand name in a manner 

that leaves no reasonable confusion that what is being sold 

is a Sunset brand filter.” Id.

Sunset appeals. We have jurisdiction under 28 U.S.C. 

§§ 1292(c)(1) and 1295(a)(1).

DISCUSSION

We review a preliminary-injunction order under the 

law of the regional circuit. Koninklijke Philips N.V. v. Thales DIS AIS USA LLC, 39 F.4th 1377, 1379 (Fed. Cir. 2022). 

The First Circuit reviews preliminary-injunction decisions 

for abuse of discretion; it reviews underlying questions of 

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4 SOCLEAN, INC. v. SUNSET HEALTHCARE SOLUTIONS, INC. 

law de novo and questions of fact for clear error. Am. Inst. 

for Foreign Study, Inc. v. Fernandez-Jimenez, 6 F.4th 120, 

122 (1st Cir. 2021).

A party seeking a preliminary injunction must establish (1) a likelihood of success on the merits of its claim; 

(2) a likelihood of irreparable harm in the absence of preliminary relief; (3) that the balance of equities tips in its 

favor; and (4) that the injunction is in the public interest. 

Together Emps. v. Mass Gen. Brigham Inc., 32 F.4th 82, 85 

(1st Cir. 2022) (citing Winter v. Nat. Res. Def. Council, Inc., 

555 U.S. 7, 20 (2008)). “The first two factors are the most 

important.” Id.

Sunset raises two challenges on appeal, both relating 

to the likelihood-of-success factor. First, it argues that the 

district court abused its discretion when it concluded that 

SoClean was likely to defeat Sunset’s defense that the 

’195 registration lacks secondary meaning. Second, it contends that the district court erred in finding that the availability of alternative designs for the filter’s head meant 

that SoClean was likely to defeat Sunset’s functionality defense. We address each in turn.

I 

We begin with Sunset’s secondary-meaning arguments. Sunset contends that the district court (1) afforded 

too much weight to the presumption of validity and (2) held 

Sunset to a higher standard of proof than the applicable 

preponderance-of-the-evidence standard. Neither contention has merit.

There is no dispute that SoClean’s trade dress is a 

product-configuration trade dress, so it is only protectable 

“upon a showing of secondary meaning.” See Wal-Mart 

Stores, Inc. v. Samara Bros., 529 U.S. 205, 216 (2000). But 

where, as here, the trade dress is federally registered, that 

registration “shall be prima facie evidence of the validity of 

the registered mark and of the registration of the mark.” 

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SOCLEAN, INC. v. SUNSET HEALTHCARE SOLUTIONS, INC. 5

15 U.S.C. § 1057(b); see also id. § 1115(a) (“Any registration 

. . . of a mark registered on the principal register provided 

by this chapter and owned by a party to an action . . . shall 

be prima facie evidence of the validity of the registered 

mark and of the registration of the mark.”). When the 

mark has been registered for fewer than five years and remains contestable, as is the case for the ’195 registration, 

“the effect of registration . . . is to shift the burden of proof 

from the plaintiff to the defendant, who must introduce sufficient evidence to rebut the presumption of the plaintiff’s 

right to exclusive use.” Borinquen Biscuit Corp. v. M.V. 

Trading Corp., 443 F.3d 112, 117 (1st Cir. 2006) (cleaned 

up). 

Though Sunset acknowledges that it bears the burden 

of showing that SoClean’s registration lacks secondary 

meaning, it nonetheless argues that the district court 

should have “decide[d] whether the evidence that was before the [trademark] examiner, in view of Sunset’s arguments and additional evidence, is sufficient to support 

SoClean’s Section 2(f) registration.” Appellant’s Br. 23–24. 

The district court agreed that Sunset had “raise[d] questions as to whether the [e]xaminer followed PTO procedures in approving” the ’195 registration.1 SoClean, 554 F. 

Supp. 3d at 296. It nevertheless presumed that the registration was valid because “Sunset ha[d] pointed to no 

1 Namely, while evidence of five years’ continuous

use is prima facie evidence that a mark has acquired distinctiveness, 15 U.S.C. § 1052(f), the Trademark Manual of 

Examining Procedure (“TMEP”) requires additional evidence for “nondistinctive product design” like SoClean’s filter, see TMEP § 1212.05(a). As the district court noted, the 

trademark examiner “granted SoClean the benefit of th[e] 

statutory presumption and approved the [m]ark” without 

requiring additional evidence of secondary meaning. SoClean, 554 F. Supp. 3d at 296. 

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6 SOCLEAN, INC. v. SUNSET HEALTHCARE SOLUTIONS, INC. 

authority for the proposition that this court may simply ignore the statutory mandate.” Id. Sunset contends that this 

was error because Congress vested courts with authority to 

review trademark registrations. Specifically, Sunset 

points to 15 U.S.C. § 1119, which states that “the court may 

determine the right to registration, order the cancelation 

of registrations, in whole or in part, restore canceled registrations, and otherwise rectify the register with respect to 

the registrations of any party to the action.”

Sunset’s argument fails. The presumption of validity 

is not conditional; the statute provides that a certificate of 

registration “shall” result in the presumption, without 

specifying any exceptions. See 15 U.S.C. § 1057(b). Sunset 

fails to identify any statutory or legal basis to withhold the 

presumption from a registration. And “withholding the 

presumption” is the basic import of Sunset’s position, no 

matter what it acknowledges about who bears the burden; 

scrutinizing the application process and deciding whether 

the trademark examiner was correct to issue the registration in the first place is the opposite of presuming that the 

registration as issued is valid. Sunset may still invoke 

§ 1119 and ask the district court to rectify the register if 

SoClean’s trade dress is deficient; Sunset simply bears the 

burden of proof in doing so, and SoClean is entitled to rely 

only on the presumption and need not present any evidence 

of its own. The district court did not, therefore, abuse its 

discretion when it declined to revisit the examiner’s actions 

and alter the statutory presumption of validity.

Sunset’s second argument—that the district court held 

it to a higher burden—fares no better. To be sure, the district court’s opinion contains a misstatement: in discussing 

the consequence of the ’195 registration’s presumption of 

validity, it said that “the burden is on Sunset, not SoClean, 

to satisfy the ‘vigorous evidentiary requirements,’ either by 

direct or circumstantial evidence, to prove that the [m]ark 

has not obtained secondary meaning.” SoClean, 554 F. 

Supp. 3d at 298 (emphasis removed). But there are no 

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SOCLEAN, INC. v. SUNSET HEALTHCARE SOLUTIONS, INC. 7

“vigorous evidentiary requirements” on the challenger for 

proving lack of secondary meaning; a trademark challenger 

need simply show invalidity of the mark—here, that the 

’195 registration is merely descriptive—by a preponderance of the evidence. See Borinquen, 443 F.3d at 117–18. 

The “vigorous evidentiary requirements,” as the district 

court noted, apply to “the question of whether a mark has 

obtained secondary meaning.” SoClean, 554 F. Supp. 3d at 

297 (emphasis added) (citing Yankee Candle Co. v. Bridgewater Candle Co., 259 F.3d 25, 43 (1st Cir. 2001)). That 

burden is on the owner of a non-registered trade dress and 

so is inapplicable here. See Yankee Candle Co., 259 F.3d at 

43, 45. So, by implying that Sunset was required to meet 

“vigorous evidentiary requirements” to prove lack of secondary meaning, it appears that the district court may 

have applied an incorrect standard.

But the oft-repeated adage that “we review judgments, 

not opinions,” applies here. See, e.g., Omega Pats., LLC v. 

CalAmp Corp., 13 F.4th 1361, 1369 (Fed. Cir. 2021). The 

district court went on to examine Sunset’s evidence of no 

secondary meaning and found it “equivocal, at best.” SoClean, 554 F. Supp. 3d at 298. Equivocal evidence plainly 

fails to satisfy a preponderance-of-the-evidence standard, 

so Sunset is wrong to suggest that the district court would 

have reached a different result had it applied the correct 

standard. The district court’s misstatement of the applicable standard of proof is harmless error. See Vanderbilt 

Univ. v. ICOS Corp., 601 F.3d 1297, 1308 (Fed. Cir. 2010) 

(finding harmless error where “[t]he district court’s findings demonstrate that under the correct legal test, [appellant] did not carry its burden”); Environ Prods. v. Furon 

Co., 215 F.3d 1261, 1266 (Fed. Cir. 2000) (“When the error 

as to the weight of proof could not have changed the result, 

the erroneous instruction is harmless.”).

Accordingly, we affirm the district court’s finding that 

SoClean is likely to defeat Sunset’s secondary meaning defense.

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8 SOCLEAN, INC. v. SUNSET HEALTHCARE SOLUTIONS, INC. 

II

We turn next to Sunset’s assertion that the district 

court misapplied the law by considering the availability of 

alternative designs after finding that SoClean’s trade dress 

is functional. Sunset contends that SoClean’s trade dress 

design “is entirely utilitarian” and that the district court 

erred by giving weight to the fact that alternative ways of 

designing the filter head existed. Appellant’s Br. 32, 37.

“[A] product feature is functional, and cannot serve as 

a trademark, if it is essential to the use or purpose of the 

article or if it affects the cost or quality of the article.” 

Traffix Devices, Inc. v. Mktg. Displays, Inc., 532 U.S. 23, 32 

(2001) (cleaned up). This “doctrine prevents trademark 

law, which seeks to promote competition by protecting a 

firm’s reputation, from instead inhibiting legitimate competition by allowing a producer to control a useful product 

feature.” Qualitex Co. v. Jacobson Prods. Co, 514 U.S. 159, 

164 (1995). “The fact that a product contains some functional elements does not, however, preclude Lanham Act 

protection.” I.P. Lund Trading ApS v. Kohler Co., 163 F.3d 

27, 37 (1st Cir. 1998). A combination of functional features, 

where the combination itself is not functional, is protectable; “[t]he crucial inquiry is into the effect that granting 

protection will have on the opportunity of others to compete.” Id.

Sunset argues that the district court, after concluding 

that SoClean’s filter design is functional, erred in giving 

weight to the possibility that the filter’s head could have 

different shapes. Appellant’s Br. 37. That premise, however, is incorrect: the district court never concluded that 

the filter’s design is functional. Rather, the district court 

said (1) that “direct evidence strongly suggests that the features of the body of” the mark are functional; (2) that “direct evidence suggests that many”—not all—“features of 

the head of the [m]ark are functional”; and (3), after a 

thoughtful discussion regarding a circuit split on the 

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SOCLEAN, INC. v. SUNSET HEALTHCARE SOLUTIONS, INC. 9

question of whether the availability of alternative designs 

is relevant indirect evidence of nonfunctionality, that alternative designs SoClean had identified for the filter head 

“constitute evidence that there are some arbitrary elements to SoClean’s filter that Sunset decided to copy where 

functionality has not otherwise been established.” SoClean, 554 F. Supp. 3d at 299–302 (emphasis added). The 

takeaway for the district court was that the ’195 registration “comprises both functional and non-functional features.” Id. at 302. That, combined with the statutory 

presumption of validity, was enough for the district court 

to conclude that SoClean was likely to defeat Sunset’s functionality challenge. Id.

Sunset is also wrong in its argument that the district 

court never should have considered alternative designs. 

Most circuits, including this court, have held that alternative designs are a relevant consideration in the functionality analysis. See Valu Eng’g Inc. v. Rexnord Corp., 278 F.3d 

1268, 1276 (Fed. Cir. 2002). The leading treatise on trademark law considers that the correct approach as well. See

J. Thomas McCarthy, 1 McCarthy on Trademarks and Unfair Competition § 7.75 (5th ed. 2021). Indeed, Sunset does 

not appear to argue that this approach is incorrect, nor do 

we believe that the First Circuit would follow a different 

path because the majority view is consistent with that 

court’s exhortation to focus the inquiry on “the effect that 

granting protection will have on the opportunity of others 

to compete.” I.P. Lund, 163 F.3d at 37. Sunset argues only 

that the availability of alternative designs should not defeat a preexisting functionality finding, but as explained 

above, that is not what the district court concluded. The 

district court, therefore, did not incorrectly apply the law.

Further, while Sunset does not overtly try to relitigate 

the functionality question, it does briefly argue about the 

functionality of the filter’s head. See Appellant’s Br. 40–42. 

In doing so, however, it relies on the same evidence that 

the district court weighed and found insufficient, and 

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10 SOCLEAN, INC. v. SUNSET HEALTHCARE SOLUTIONS, INC. 

Sunset does not identify any clearly erroneous findings or 

other abuse of discretion. Accordingly, we affirm the district court on the functionality issue as well.

Finally, the district court noted that, under the Trademark Modernization Act of 2020, SoClean is entitled to a 

rebuttable presumption of irreparable harm once the court 

has found that SoClean is entitled to a likelihood of success 

on the merits. Sunset did not attempt to rebut that presumption. As for factors three and four, the district court 

concluded that the balance of the equities and considerations of public interest weigh in SoClean’s favor, and Sunset has likewise not challenged those findings on appeal. 

We also note the narrowness of the preliminary injunction. 

For all of these reasons, we affirm the district court’s grant 

of the preliminary injunction.

CONCLUSION

We have considered Sunset’s remaining arguments 

and find them unpersuasive. We affirm the district court’s 

preliminary-injunction order.

AFFIRMED

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