Polar A300 Fitness and Activity Tracker with Heart Rate Monitor, Black Provides everyday feedback to guide you towards a more active lifestyle, Tracks daily activity, calories, steps and distance covered, Vibrating inactivity alerts help you keep moving throughout the day Syncs with free Polar Flow app and web service for additional workout planning, motivation and guidance H7 Bluetooth Smart heart rate sensor included for continuous, accurate heart rate, Powerful, rechargeable battery lasts up to four weeks, Easily charges with simple plug and play USB Automatically tracks your sleep time and quality, Get a better understanding of your sleep patterns and how they affect your activity levels, Requires chest strap for accurate heart rate. Changeable wristband, Six additional vibrantly colored wristbands are sold separately, Fully waterproof for swimming Resolution: 64 X 28; Water Resistance: WR30