The Coilhose Pneumatics 5901 3/8" Automotive Air Plugs with 3/8" Male Pipe Thread are engineered to interchange with the Automotive Tru-Flate interchange designs of other manufacturers. The Coilhose 5901 connectors are machined from steel, then plated to provide years of service. Steel connectors offer a harder sealing surface that is more resistance to dings and scratches. This style of plug is most commonly used in pneumatic nailers and staplers.