Pro-Form Smart Beat Chest StrapMake your compatible phone or tablet work for you by combining it with the Pro-Form Smart Beat Chest Strap. When paired with a compatible device, the Smart Beat Chest Strap monitors your heart rate with ECG accuracy. It is Bluetooth enabled and has dual transmission modes (BLE and 5khz). It has a durable, water-resistant design, but it not recommended for swimming. Replaceable battery Compatible with the following devices: Droid Razr, Samsung Galaxy SIII, iPhone 4s, iPad 2012, MacBook Air 2012 and Apple Mace Mini 2012.