Vetus air vents prevent sea water from siphoning back through the exhaust into marine engines. Also called a vented loop, it is used as a siphon break for marine toilets and holding tanks. This siphon break is critical for engines utilizing a wet exhaust system. Two different models are available: type ASD and type AIRVENT. Both models can be connected to hoses with internal diameters of Ø 13, 19, 25 and 32mm (½”, ¾”, 1” and 1¼”). Version ASD38 connects to hose with internal diameter of Ø 38mm (1½”).