Once you've mounted the Throttlemeister bar ends to your bike, they work like this: All of the workings of the Throttlemeister are inside the bar end itself. Once mounted, you turn the whole bar end in the same direction as opening the throttle. A piston moves in and out of the Throttlemeister itself and puts friction against the throttle tube, which in turn counteracts the throttle return spring. When installed properly, the Throttlemeister will not completely lock the throttle. You can always override the Throttlemeister in any situation. If you need to stop quickly you can just grab the throttle and turn it off.
