Description Elegant, intelligent activity tracker combines stylish design with sleek metal accents and a vivid, easy-to-read display. Offers advanced sleep tracking, including REM sleep, and can measure blood oxygen saturation levels overnight using the wrist-based Pulse Ox sensor. (Not intended for medical diagnosis or monitoring). Health and fitness tools include estimated heart rate tracking, all-day stress monitoring, relaxation breathing guide, VO2 max, energy monitor, and more. Includes dedicated timers for various activities like walks, runs, strength training, yoga, and pool swims. Receive vibration alerts for all notifications, including calls and messages (Android users can reply to texts). Battery life lasts up to 7 days (excluding Pulse Ox sleep tracking) and is water-resistant for swimming and showering.