GPS model lets you take calls and reply to texts from your wrist
Measure your blood oxygen with an all-new sensor and app
Check your heart rhythm with the ECG app
The Always-On Retina display is 2.5x brighter outdoors when your wrist is down
S6 SiP is up to 20% faster than Series 5
5GHz Wi-Fi and U1 Ultra Wideband chip
Track your daily activity on Apple Watch and see your trends in the Fitness app on iPhone