1/4" Automotive Standard Series Type "C". Plated steel couplers have hardened steel balls and stainless steel springs. Coupler plugs are heat treated to reduce wear on critical mating surfaces. The Automotive Series couplers interchange with Tru-Flate 10 and 100 type series as well as units produced by other manufacturers. Maximum working pressure 300 PSI. Male, 1/4" NPT Size, Steel. Coupler.