The titanium case measures 49 mm. Available carbon-neutral combinations One Retina display that is always on As much as 3000 nits SiP S9 Double-tap motion Quicker on-device Siri that can access health data Accurate Location for the Blood Oxygen App on the iPhone 2 3 ECG applications 4 Notifications of elevated and decreased heart rates Four irregular rhythm alerts 5 Notifications of Low Cardio Sensing temperature 6 Tracking cycles with estimates of ovulation in retrospect 7 Emergency SOS 8 Calling for emergencies abroad 9 Identifying Falls and Crash Events 8 Siren Water-resistant 12 Waterproof Water sports at high speeds 40-meter recreational dive Accurate dual-frequency GPS cellular communication 13 Facilitates Family Configuration (GPS + Cellular models) 14 Family members without iPhones can be connected. 36 hours of typical use 18 72 hours or more in low power mode