Parker 339 Series check valves are designed for allowing free flow of air in one direction while preventing zero flow in reverse direction, ensuring smooth operation in industrial equipment. These units feature heavy-duty brass construction for low friction and corrosion resistance and have urethane seals to provide tight tolerances and excellent abrasion and chemical resistance in harsh environments. They provide female to female connections to form a positive seal between the valve ports and pipe ends. Choose from a wide range of these check valves, available in NPT and BSPP port variants.