Fitbit Alta HR, Black, Small (US Version)

Specifications:

• 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.
• 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.
• See how working out more can improve your health by comparing your resting heart rate trends to your activity.
• Automatically track your steps, distance, calories burned and active minutes with up to 7 days of battery life