The polar h1 heart rate sensor is made from a soft textile material ensuring ultimate comfort of wearing the heart rate sensor seamlessly adapts to the body enabling the athletes to focus on the workout it features slim and streamlined connector design and replaces the wearlink transmitter set additionally the h1 sensor has an improved user replaceable battery mechanism and is compatible with most polar products including the ft1 ft2 ft4 ft7 ft40 ft60 ft80 rcx5 rs400 rs300x rs100