Comfort is key when training, so Polar created the Polar WearLink+ transmitter belt It not only measures your heart rate but also seamlessly adapts to your body shapes so you feel as if it\'s not even there. The transmitter consists of an electrode strap and a connector, and with its side-clip mechanism, it\'s as quick to put on as it is to take off.Soft textile material feels like clothing on the skinErgonomically designed to feel like it\'s a part of yoRemovable and machine washable textile strapUser replaceable batteryCompatible with the following Polar products: FT60 FT40 CS300 FT7 RS400 FT4 FT2 RS300X FT1 RS100 CS200cad CS100