COLMi R03 Smart Ring 18.9mm, Black

The COLMi R03 is a smart ring sized 18.9mm and finished in black, weighing just 4.7g. It tracks heart rate, blood oxygen and sleep, supports 21 sport modes, and is rated 5ATM water resistant. It runs 3-5 days per charge, recharges in about an hour, and its included charging case can recharge the ring up to 13 times. Data syncs to the QRing app on Android and iOS.