Korean cosmetic medical device company SkinRex Co. is in hot water with the FDA after the federal watchdog agency issued a warning letter over the marketing of its Cavi-Lipo device.

Seoul-based Skinrex is focused on skincare and weight issues. The company, founded in 2002, is led by Se-Yeong Choi and markets 3 products.

The Cavi-Lipo is an ultrasound cavitation system that uses ultrasound waves to dissolve cellulite and treat adipose areas. The device was launched in Japan in 2008 and won CE Mark approval in Europe in 2010, according to the SkinRex website.

But the FDA says SkinRex never sought clearance or approval to put the Cavi-Lipo device on the U.S. market, according to the warning letter. The device does not have premarket approval or an investigational device exemption, making it illegal to be sold in the U.S., according to the letter, despite Internet reports and spa website descriptions identifying it as an “FDA Class 1” device.

The Cavi-Lipo device is also misbranded as an “electric therapeutic massager,” according to the agency, which would exempt it from some regulatory requirements for medical devices. The FDA found that the device does not qualify as an electric therapeutic massager because it’s used “for the temporary reduction in the appearance of cellulite” using ultrasound diathermy, not “mechanical vibration to manipulate tissue,” according to the letter.

“FDA is taking steps to refuse entry of these devices into the United States, known as ‘detention without physical examination,’ until these violations are corrected. In order to remove the devices from detention, your firm should provide a written response to this warning letter as described below and correct the violations described in this letter,” the agency said.