Air Vent Head Size: 50A-500A Pressure: 10k, 16k Type: A, AS, B, ... , C, CS, D, DS, E, ES Air Vent HeadAir Vent Head can be used on water tank and oil tank.Size ... :Oil Tank Air Vent head has character of cover on top of head.Water Tank Air Vent head has character of permeability on ... in ballast bilge. We have many choice of Air vent head, please contact me for more products information