Miltons 2-In-1 Universal Safety Exhaust couplers safely bleed excess air pressure and disengages fittings without dangerous blow-back from trapped pressure inside your air line or hose. This 1/2 FNPT industrial air coupler can be used to safely disconnect your air tools from the hose eliminating the threat of potentially dangerous hose whip. Instead, the air hose coupler remains connected to the plug while pressurized air is safely bled off. The universal design provides air compressor fittings compatible with two interchanges: G-Style 0.125 and 0.375. This sturdy coupler fitting is made of heavy-duty steel, making it the ideal air compressor accessory for any air hose or pneumatic tool that requires a long-lasting pneumatic coupler. PATENT # US D1,010,072 S.