The feature was removed on select smartwatches due to a patent-infringement lawsuit, but Apple has “redesigned” it.

Apple just reintroduced a blood-oxygen reading feature to some Apple Watches last week, but a new lawsuit could force the company to turn it off again.

Masimo is back in court defending its blood oxygen patent, this time it's taking on the U.S. government, alleging it's allowing Apple to infringe.