Auction Title will be here!Product Description Fabric Strap: Medical Polyester (80%Nylon and 20% Spandex) XOSS HR chest strap Provides live, accurate heart rate to compatible mobile training apps through Bluetooth Smart technology The Chest Strap heart rate is an early warning for the health(HR max of different people is not the same, the estimated formula is 208-0.7*Age Adjustable elastics strap.Battery life will last up to 1 year and low power consumption. Waterproof sensor, For Iphone 4s/5/5s/6/6s/7 plus and for other Android 4.3 devices Note, the black color has 2 mode,black bluetooth&ANT only this model support 2 conntection method.New Brand ,High quality, Good Service. We have sold a lot of pieces this product , the customers always satisfied with our service.