Polar H6 Heart Rate Sensor 2" high 5" wide Provides live, accurate heart rate to compatible mobile training apps, including Polar Beat Uses Bluetooth Smart technology providing ECG-accurate heart rate to any Bluetooth Smart ready device utilizing standard heart rate profile Compatible with iPhone 4S, iPhone 5, iPod touch (5th generation), iPad (3rd & 4th generation), iPad mini and iPod Nano (7th generation) User replaceable battery. For optimal battery life, detach transmitter from chest strap after every use Does not provide heart rate to Polar heart rate monitors