... /4", 1" Surface: brass/nickel plate Automatic air vent valve, brass air release valve, gas valveMaterial: brassSize: 1/2", 3/4", 1"Surface ... in producing all series of brass air vent valves, brass release valves, brass safety valves which widely use in heating systems ... to send us inquiry for further cooperation! Automatic Air Vent Valve Brass Air Release Valve