Halo m4 500w electric scooter throttle unitplease note that there are multiple versions of this throttle, please ensure that the serial number on the back of the throttle matches the throttle you are ordering otherwise it may not work on your scooter.old dy is for the older control box model dynew zkw is for the newer control box model zkw. This throttle has a white label on the back, instead of a serial number.