Fitbit Alta HR, Black, Small (US Version)

Features

• 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 purpose 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)