When it comes to athletic sneakers, many are so similar in design that they can be hard to tell apart.

But those little details make a difference — and those in the shoe business the longest are apt to notice if another company’s design looks suspiciously familiar.

Related: Nike is facing a problem with one of its most beloved products

Nike NKE recently had this unfortunate experience, leading the legacy shoemaker to file a federal lawsuit on Nov. 6 against New Balance and Sketchers SKX.

The details of the suit claim that Sketchers and New Balance are misusing Nike’s Flyknit technology, which are used in the uppers of its sneakers and took more than a decade to develop. The shoes in question include New Balance’s Fresh Foam, FuelCell, and other lines, as well as Skechers’ Ultra Step and Glide Step brands.

Nike requests an unspecified amount of money for damages, as well as court orders to block New Balance and Sketchers from infringing on the patents.

New Balance replied to the lawsuit’s claims with a statement that it “fully respects competitors’ intellectual property rights, but Nike does not own the exclusive right to design and produce footwear by traditional manufacturing methods that have been used in the industry for decades.”

TheStreet has reached out to Skechers for comment.

Related: Nike has an unusual new way to sell Air Jordans

Nike has also sued Adidas and Lululemon in the past with claims that the two companies infringed on Flyknit. Adidas, which originally filed its own countersuit, was settled in Aug. 2022. when the two companies filed to jointly dismiss the case. The Lululemon lawsuit , which was filed in Feb. 2023, has yet to be resolved.

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