... 1 / 4", 3 / 8", 1 / 2"; Name: USA interchange adaptor(universal coupler, combo coupling); Body: 1/4"; Thread: NPT (National Pipe ... Thread size: 1 / 4", 3 / 8", 1 / 2"; Coupler type: Universal type, combo type, 3 in 1 type; Surface treatment: Zinc ... degree Centi; Application: Pneumatic tools, general air connections, air piping systems, air pressure equipments; The quick couplers include: Female thread ...