Utilize 24/7 heart rate to more accurately track calorie burn, resting heart rate and heart rate zones during workouts - Track all-day activity, including steps, distance, hourly activity, active minutes and calories burned - Automatically track sleep, plus due to the heart rate feature, get more insights into your light, deep and rem sleep stages - Enjoy up to 5 days of battery for daily progress without constant charging. Varies with use and other factors - Automatically and conveniently record workouts like walks, swimming and bike rides in a snap with SmartTrack - Effortlessly Compatible: Automatically syncs to 200+ Android, iOS & Windows 10 devices so you can see your progress in the app.