Features1Heart rate detection can directly understand the heart rate during exercise to avoid physical damage caused by over-exercise. At the same time, understanding the heart rate can easily control the exercise intensity, keep it at an appropriate level, and the exercise effect will be better. 2It can support BT 4.0 and ANT+ protocol at the same time, monitor exercise heart rate in real time, and wirelessly send data to mobile phone APP, sports watch, stopwatch and other devices to record your every exercise heart rate. 3Wear comfortably, size 6490cm below the chest line; wear tightly, size 90110cm / 25.235.4in below the chest line. The size below the chest line is more than 110cm / 43.3in, it is not suitable to wear, so it is not recommended to buy. 4Sensor will sleep if no data is detected for 20 seconds, and the device cannot be detected after sleep. When the device detects data for three seconds, it will automatically wake up and transmit data. 5Running, cycling, fitness, mountaineering, yoga and other sports can detect your heart rate output in real time through auxiliary equipment! Let you have a healthy exercise! 6ANT+ protocol, compatible for GARMIN sports watch & stopwatch, for Bryton , for IGPSPORT, for ZWIFT, for ONELAP, for BKOOL, for TACX and other virtual riding training software. 7BT protocol, compatible for Songtuo BT sports watch, for Walker, for Qiji, for Blackbird Ride, for Tulip Sports, for STRAVA.SpecificationItem Type: Heart Rate Sensor HostMaterial: ABS HostHost Size: Approx. 61.9 x 34.3 x 10mm / 2.4 x 1.4 x 0.4inChest Strap Size: Approx. 64-86cm / 25.2-33.9inWeight: Approx. 72g / 2.5ozWireless Interface: BT 4.0, ANT+Heart Rate Range: 30-240BPMBattery: 1 Button Battery CR2032, Capacity 240mAh (Built-in Battery Shipped)Battery Life: Up To 1000hWaterproof: IP67Suitable for Various GPS Code Tables: for Bryton 310 330 405 530, forGarmin's Full Range (Except forGarmin 200), for IGPSPORT Igs50 Igs618, for Blackbird BB10S, for XOSS SPRINT, for XOSS G+, and Other ANT+ Code Table Equipment UseAlso Suitable for All Kinds of Sports Watches and Mobile Cycling Apps in ANT+ Mode: for Walker, for Blackbird, for Qiji, forTulip, for Gudong, for Yuehuan and so onPackage List1 x Heart Rate Sensor Host1 x Chest Strap