For systems where cooling water is injected into the exhaust less than 15 cm above the waterline, there is a risk that cooling water will siphon into the exhaust system and subsequently into the engine itself when the engine is stopped.Such siphoning may be prevented by fitting a Vetus air vent at least 40 cm above the waterline. Type V has a reliable anti-siphon pressure valve and is self-contained. However, it requires periodic maintenance to prevent clogging with salt crystals.Can be connected to hoses with internal diameters of 13, 19, 25 and 32 mm