Fitbit Alta HR, Blue/Gray, Small (US Version)

Get the power of continuous heart rate in Fitbit's slimmest design yet-all day, during workouts and beyond
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With heart rate, you can better measure calorie burn, and use zones (Fat Burn, Cardio, and Peak) to find the right workout intensity for your goals.
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With sleep stages powered by PurePulse heart rate, automatically track your time spent in light, deep and REM sleep and take steps toward a better night's rest.
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See how working out more can improve your health by comparing your resting heart rate trends to your activity.
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Automatically track your steps, distance, calories burned and active minutes with up to 7 days of battery life. Syncing range: Up to 6.1 m; Syncing requires Bluetooth LE and Internet connection. Windows 10 computers that do not have Bluetooth 4.0 LE will need a wireless sync dongle in order to sync; Syncs with Mac OS X 10.6 and up, iPhone 4S and later, iPad 3 gen. and later, Android 4.4 and later, and Windows 10 devices . Operating temperature 14° to 113° F