Amazon.com: Fitbit Alta HR, Black, Small (US Version): Gateway

About the product     Get the power of continuous heart rate in Fitbit's slimmest design yet-all day, during workouts and beyond 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 See how working out more can improve your health by comparing your resting heart rate trends to your activity 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 Automatically track your steps, distance, calories burned and active minutes with up to 7 days of battery life (varies with use and other factors) Fitbit does not guarantee the quality or authenticity of products purchased from non-authorized resellers on Amazon, and they are not eligible for warranty/replacement. Authorized Fitbit retailers: Amazon.com, Heart Rate Monitors USA and Clever Training NOTE: Refer the User Manual befo