Under Armour filed a trademark infringement lawsuit accusing an athletic apparel brand called HOTSUIT of copying the Baltimore brand’s famous logo, according to a story in The Baltimore Sun.

The Sun story reports that Ageas Inc., based in Denver, has been advertising and selling HOTSUIT-branded sports and fitness apparel, footwear and accessories displaying a logo similar to the Under Armour’s black logo linking an upside down U with an A, the lawsuit says.

The HOTSUIT brand was officially founded in Denver in 1999, according to the company’s website, which offers the following back story about the logo’s design and its connection with the face of a digital watch:

To embody the major feature of HOTSUIT—better effects of exercise in a shorter time—the LOGO integrated the brand’s initial letter ‘H’ and the electronic watch code that people will recall upon mentioning time 7-digit code. This tells a story of time and efficiency.

According to the website, HOTSUIT began by selling sauna suits, branded as ‘HOT’ + ‘SUIT’.

“At first, this was a high-end niche brand for professional athletes and artists to lose weight in the shortest time possible; later, the suits were widely used by young people for body shaping. Nowadays, the product line extends to running, fitness, leisure and other categories, and it is a sought-after brand in many countries around the world,” the website states.