Apple will reintroduce its blood oxygen measurement feature to certain Apple Watch models in the United States following government approval, the company said on Thursday.

The update, to be delivered via software, will be available for the Apple Watch Series 9, Series 10, and Apple Watch Ultra 2.

The move comes after a lengthy legal battle with Masimo, a California-based medical technology company that accused Apple of poaching employees and misappropriating its pulse oximetry technology.

Masimo won a 2023 U.S. International Trade Commission ruling blocking imports of Apple’s Series 9 and Ultra 2 watches with the feature, prompting Apple to remove it from models sold in the U.S.

Apple said the affected watches were shipped without the blood oxygen function, but U.S. Customs has now approved its restoration. Once updated, users can initiate a session in the Apple Watch’s blood oxygen app, with sensors collecting data that will be processed and displayed on a paired iPhone.

Apple first added the feature in its Series 6 model in 2020, while Masimo launched its competing W1 watch in 2022. Shares of Masimo fell 4.5% on Thursday following Apple’s announcement.