The Crampbuster provides a way for comfortable throttle control and dramatically reduces the wrist fatigue often caused by long rides. It doesn t lock the throttle on and installs with no tools just slide it on it rotates forward with ease yet when downward pressure is applied by your hand the throttle is regulated effortlessly without squeezing. There are no moving parts or tools required. It works on the principle of an oil filter wrench. Simply stretch it open and snap it on the outside of your grip. It will rotate clockwise (upward for adjustment) but when turned counter clockwise (downward) by the weight of your palm it pinches and the throttle is pulled open. To accelerate simply lift it a little (causing it to rotate up clockwise) then rest your palm back on it. To decelerate simply spin it up clockwise completely around until it comes up into a position a little lower than before. It can also be used as a rest for you left hand. Standard size fits grips that are under 1-3/8 inches in diameter and has shorter and wider palm rest.