Polar Loop Activity Tracker with H7 Bluetooth Smart Heart Rate Sensor Bundle 24/7 activity tracker provides guidance and motivation to help you reach your goals. Shows daily activity, feedback, calories burned, steps and time Includes H7 Bluetooth Smart heart rate sensor (M-XXL) for accurate heart rate and calorie tracking during indoor cycle classes, yoga and more Tracks sleep duration and quality. Flow app and web service give a detailed look into how you sleep and how changes in your daily life can affect it Displays whether you are in your fat burning or fitness improvement heart rate zone during your workout with the Energy Pointer feature Custom fit band is waterproof for swimming. Rechargeable battery. Auto syncs to free Polar Flow app and website