41 mm of aluminum Available carbon-neutral combinations One Retina display that is always on 2,000 nits or more 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. Water-resistant 11 GPS that is swimproof Cellular connectivity that is available 13 Facilitates Family Configuration (GPS + Cellular models) 14 Make connections with family members without iPhones 18 hours of typical use 16 36 hours or more in low power mode 16 Quick charging 17