A U.S. federal trade agency on Thursday found that Apple violated the patent of a rival tech company, a ruling that could lead to an import ban for certain models of the company’s smartwatch.

The case revolves around medical-technology company Masimo, which alleged in a 2021 complaint to the U.S. International Trade Commission that Apple violated its patents related to measuring blood-oxygen levels. Apple has included a sensor, called a pulse oximeter, in most new models of the Apple Watch since 2020.