... ; Body size: 1/4", 3/8", 1/2"; Name: USA Industrial Type Air Couplers, Milton type(Air Coupler, Air Tool Coupler ... : 1 / 4", 3 / 8", 1 / 2"; Coupler type: Milton type, Industrial type; Surface treatment: Zinc plated, acid washing; Working pressure: No ... , all the sockets and plugs will be strictly tested for its working pressure, air leakage, surface finishing and thread test. Industrial Coupler