Original Yamaha replacement speed sensor for PW and PW-X motors. Via the speed sensor, the Yamaha motor measures the exact speed of your e-bike. Only with this can the motor work properly and provide you with the right power. The change of the Yamaha speed sensor for e-bikes can be easily done by yourself. For the measurement of the correct speed, the speed sensor also requires the matching Yamaha spoke magnet, this is available separately.