1/4" male national pipe thread 1/4" coupler. Interchangable with most ARO® series couplers and plugs produced by other manufacturers. Features zinc plated solid brass bodies and sleeves with stainless steel springs, hardened steel locking balls and valves, and Buna-N (Nitrile) seals. Precision machined bar stock construction provides resistance to the effects of mechanical shock in rugged applications.