sleep tracking
The rumor jibes with recent comments Apple VP of Health Dr. Sumbul Desai made to MobiHealthNews about sleep.
The filing is a strong indication the Cupertino tech giant isn't done with standalone sleep monitoring devices.
On the Prince's trip to New Zealand and Australia he was seen donning the wearable which uses heart rate, motion and temperature sensors to track a user's sleep.
The device senses blood oxygenation, heart rate, sleep position, and stopped breathing events.