Dixon 56-400 Steel Hydraulic Quick-Connect Fitting, Coupler, 1/2" Coupling x 1/2"-14 NPT Air Chief industrial interchange quick connect coupler for connecting directly with a hose with a female NPT end to connect with a male NPT threaded connection Industrial interchange check valve coupler with a female NPT threaded end Two-way check valve permits fast operation with minimal loss of fluid Steel for stronger welded joints and greater rust resistance than wrought iron Interchanges with Series A in ISO 7241-1 which describes interface dimensions and basic performance requirements