This sensor uses a magnet to send throttle or brake position data to your MyChron4 kart data logger. Simply install the magnet on the pedal near the pivot, install the sensor in front of the magnet on the chassis, and calibrate using the MyChron4 calibration page. Measures up to 35mm of pedal travel (magnet-to-sensor distance must be no less than 5mm at full throttle and no more than 40mm at zero throttle). Can be used on either brake or throttle pedal. Requires eBox, sold separately.