Volvo Penta 19mm anti syphon, vacuum valve, part number 21662702.
This vacuum valve or anti-syphon valve is for vessels with an engine installation at or below the waterline. It is suitable for all makes of diesel including Volvo Penta, Yanmar, Beta, and Vetus. A vacuum valve must be installed to prevent siphonage from occurring through the seawater intake, resulting in water ingress into the engine.
This 19mm version is used when using 19 mm water pipe to connect the engine.
Volvo Penta Part No: 21662702