Footwear company Crocs is suing Five Below over the design of the company's discount clogs and the charms used to personalize them, alleging the cheaper brand infringes on several patents and a trademark.

The federal lawsuit claims Five Below did not stop selling the disputed products even after Crocs sent demand letters earlier this year detailing the similarities and the patents in question. Crocs alleges the Juniors Charm Clogs sold at Five Below copy the design of its Classic Clogs and the charms offered by the discount retailer are knockoff versions of the Jibbitz pieces that can be placed in the holes in a pair of Crocs.

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The lawsuit filed in federal court in Colorado, where Crocs is based, notes the stark difference in price between Five Below's clogs and the versions Crocs became known for when the brand debuted in the early 2000s. Five Below, which is headquartered in Philadelphia, sells its Juniors Charm Clogs online for $7. Crocs' Kids Crocband Clogs retail for $44.99.

The complaint claims Five Below's shoes are "likely to cause confusion among customers" and be mistaken for Crocs' products.

Five Below did not respond to a request for comment about the lawsuit. The chain's Center City store did not have any of the clogs covered in the lawsuit on display Thursday afternoon. 

Crocs had an initial wave of popularity when the brand debuted in 2002, followed by a second surge in sales that started about a decade ago. High fashion designers, including Balenciaga and Christopher Kane, collaborated with the company to elevate the appeal of its clogs. Rapper Post Malone also worked with the company on a series of limited-edition designs and other celebrities helped introduce the clogs to a younger generation. The company's revenue spiked during the COVID-19 pandemic as Crocs capitalized on comfort apparel for people working from home.

Fashion patent cases are known to be challenging to win in court, Inc. reported, since the owners of intellectual property need to prove that competing designs are deliberate and obvious imitations. The Fashion Law blog noted that Crocs' lawsuit targets both the design of Five Below's clogs and the "system" of pairing them with decorative charms. Jibbitz is a subsidiary of Crocs.

Five Below has been hit with similar lawsuits over alleged duplicate products in recent years. Skincare brand Supergoop recently alleged Five Below's Sugar Girl sunscreen line mimicked its logo, packaging and product names. The maker of Stanley drinkware also sued Five Below last year, alleging some of its products are imitations of its drink containers.

Crocs' lawsuit seeks a jury trial and unspecified damages for lost profits and legal fees. The company also is seeking a court injunction to prevent Five Below from selling the products that allegedly infringe on Crocs' intellectual property.