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