Overview 44mm or 40mm aluminum case size Retina display Up to 1000 nits High and low heart rate notifications Irregular rhythm notifications Low cardio fitness notifications Sleep Tracking Vitals app featuring heart rate, respiratory rate, and sleep duration Cycle Tracking Emergency SOS International emergency calling Fall Detection and Crash Detection Water resistant Swimproof GPS Available cellular connectivity S8 SiP Siri Find iPhone Up to 18 hours normal use Low Power Mode What’s in the Box Case Band Apple Watch Magnetic Charger to USB-C Cable (1 m)