2 pack, 1/4" npt, female, i/m style, plug, case hardened steel plated to resist rust, 1/4" basic flow size, offers maximum of 300 psi, air flow of 40 standard cuft per minute, maximum temperature of 250 degrees fahrenheit, milton m/i style kwik change couplers & plugs will interchange with all manufacturers who comply with the dimensional requirements of military specification mil-c-4109.