Set contains one 6-5106 1/4" national pipe thread 1/4" female coupler and one 6-5101 1/4" national pipe thread 1/4" male nipple. Interchangable with most Industrial 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. Plugs are plated steel with hardened wear points. Precision machined bar stock construction provides resistance to the effects of mechanical shock in rugged applications.