... , AS, B, BS, C, CS, D, DS, E, ES Air Vent HeadAir Vent Head can be used on water tank ... and oil tank.Size: 50A-500APressure: 10k, 16kType: A, AS, B ... : JIS-KS91A-121, CB/T3594-94, 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 side ...