ProForm SmartBeat Flexible Heart Rate Monitor Strap: * Heart rate monitor chest strap * Durable, water-resistant design (not recommended for swimming) * Replaceable battery * ECG accurate * Dual mode transmission (BLE and 5kHz) * Bluetooth smart * Compatible with the following devices: Droid Razr, Samsung Galaxy SIII, iPhone 4s, iPad 2012, MacBook Air 2012 and Apple Mac Mini 2012