Key Features 49mm titanium case Always On Retina LTPO OLED display up to 3000 nits. Double tap gesture ECG app: High and low heart rate notifications, Irregular rhythm notifications and Low cardio fitness notifications Sleep tracking: Sleep apnea notifications Vitals app featuring heart rate, respiratory rate, wrist temperature, and sleep duration Temperature sensing: Cycle Tracking with retrospective ovulation estimates Emergency SOS: International emergency calling, Fall Detection and Crash Detection, Siren 100m Water resistant: Swimproof, Depth gauge to 40m, Water temperature sensor, High-speed water sports & Recreational scuba to 40m Precision dual-frequency GPS, Cellular S9 SiP: Double tap gesture, Fast on-device Siri with health data access & Precision Finding for iPhone Up to 36 hours, Up to 72 hours in Low Power Mode & Fast charging (0-80% in about 1 hour)
