This cover allows you to loosen and tighten the CO2 puncher screw without tools for quick insertion of the CO2 cartridge. To install place punch button cover over the splines of the punch button and tighten. Once tightened you may need to remove the punch button cover and place it closer to the straight position. It may be necessary to loosen the puncher screw until the cover is straight. Once aligned you are able to tighten and loosen the puncher screw without tools.