The Scosche Rhythm+ 2.0 is a powerful tool for cyclists, runners and anyone who likes to keep fit outdoors. It uses precision biometrics to measure blood flow and calculate hyper-accurate heart rate measurements, allowing you to track your fitness data.The comfortable design allows you to wear it on your bicep, tricep or forearm - no more restrictive chest straps! The battery lasts up to 24 hours and the armband boasts a 100ft range with dual-mode connectivity to Bluetooth and ANT+ devices. Heart Rate Monitor with precision biometrics24 Hour Battery LifeWireless up to 100 ft. rangeGreen/yellow optical sensor arrayWorks with 200+ fitness apps Durable IP68 design - waterproof & dustproofDual-Mode Radio transmits to both Bluetooth and ANT+Comfortable strap fits to bicep, tricep or forearm