Polar created the Polar WearLink®+ with WIND technology on the T31 transmitter belt to eliminate interference from external influences such as power lines. With the T31 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 new side-clip mechanism, it’s just as quick to put on as it is to take off.