Fitbit Alta HR - Fitness Activity Tracker Model #: FB408 Band Color: Black in Very Good Used Condition Tested and Fully Functional About this item:Get the power of continuous heart rate in Fitbit's slimmest design yet-all day, during workouts and beyondWith heart rate, you can better measure calorie burn, and use zones (fat burn, cardio, and peak) to find the right workout intensity for your goalsSee how working out more can improve your health by comparing your resting heart rate trends to your activityWith sleep stages powered by purpose heart rate, automatically track your time spent in light, deep and REM sleep and take steps toward a better night's restAutomatically track your steps, distance, calories burned and active minutes with up to 7 days of battery life (varies with use and other factors) What's in the Box:Fitbit Alta HRUSB ChargerDocumentation