Wahoo Trackr Heart Rate Monitor. Accurate reliable comfortable and connected the Wahoo Trackr Heart Rate monitor offers athletes everything they need from a heart rate sensor to take their performance to the next level.Strap Length: Adjustable from 27″ to 36″ (68cm to 91cm)Maximum Chest: Fits up to 50″ (127cm) chestsConnectivity: ANT+ and up to three Bluetooth connectionsSupported Devices: iOS – iPhone iPad Mac Android devices WindowsBattery: Rechargeable Lithium IonBattery Life: Over 100 Active HoursSweatproof: Yes handwashable strapWater Rating: IPX7 up to 1 meter for 30 minutes