The damage and distortion that typically happens with plastic bleeder screws from the high under-hood temperatures and routine use will no longer be a problem. Billet aluminum makes the PPE Air Bleeder Screw a lot stronger and weather-resistant. The new redesign makes for quick and easy operation with either a flat-head screwdriver or nut driver. The machined air channel on the threads functions to bleed air. Beware of inferior bleeder screws without an air channel. The channel lets air escape without completely removing the screw. 2001-2016 GM 6.6L Duramax Air Bleeder Screw Black