Muffler/filters effectively reduce air exhaust noises to an industry accepted level with minimum flow restriction. They protect valves, impact wrenches, screw drivers and other air tools by preventing dirt and other foreign matter from entering the system. Non-corrosive. Can be cleaned with many common solvents. Ambient temperatures below freezing require moisture-free air. Ambient temperatures below freezing and above 180 degree require lubricants especially selected for suitability at these temperatures. Pneumatic valves should be used with filtered and lubricated air.11/16" Hex Size