“IMPERIAL” QUICK DISCONNECT COUPLER PLUG Body Style: 3/8″ Male NPT: 1/4″ Case hardened plugs. Corrosion immune finish. Maximum Air Pressure: 300 psi Male Pipe Thread, Automotive (Tru-Flate) Design. Manufactured of high-grade alloy steel. Heavy-duty quick disconnect Male coupler body. For low pressure pneumatic lines primarily used for air.