High Quality Valve Extender for 40mm Deep Rim CNC Aluminum Alloy Finish Set of 2 with caps This is a "transition type" valve extender. How to install is 1) Remove the valve core, 2) Attach the screw end of the valve extender to the stem on the tube or tubular side 3) Tighten the recess at the end of the valve extender, 4) 1) Put the valve core off back into the valve extender top and youre done. The screw part of the valve extender is the same screw shape as the valve core, and comes with a gasket to prevent air leakage.