Lululemon Athletica claims in its lawsuit filed in the U.S. District Court for the Central District of California that Costco has “unlawfully traded” on its reputation, goodwill and sweat equity by selling unauthorized and unlicensed apparel that uses knockoff, infringing versions of its patents.

Vancouver-based Lululemon asserts that Costco sells apparel that mimics the look and feel of its products.

Lululemon filed a lawsuit against Costco, claiming the company has been selling lower-priced duplicates of some of its products.