Air Vent Head Size: 50A-500A Pressure: 10k, 16k Type: A, AS, B, BS, C, CS, D, DS, E, ES Air Vent HeadAir Vent Head can be used ... -94, DIN, ISONote:Oil Tank Air Vent head has character of cover on top of head.Water Tank Air Vent head has character of permeability on two ... mainly used in ballast bilge. We have many choice of Air vent head, please contact me for more products information