Apple Watch Series 8 features 45 mm or 41 mm with Aluminium case with Sport Band Always-On Retina display Up to 1,000 nits IP6X dust resistant and Swimproof Blood Oxygen, ECG, Hear rate, Temperature sensing, Cycle Tracking with retrospective ovulation estimates Emergency SOS, International emergency calling, Fall detection, Crash detection GPS + Cellular connectivity Colors: Midnight Black, Stralight, and Silver