Flush Pro Valve - 1Finally! Freshwater flushing of your inboard is as simple as connecting a garden hose.Features:PolymerStainless Steel SpringFlush your boat engine safely and easilyTransparent body allows for visual inspection of water flowDurable check valve system activated by water pressure from a garden hoseCheck valve automatically shuts off hull intake when water pressure is applied Adapter supplied with Flush Pro make winterizing your boat easyCan be used with on board generatorsAvailable for Standard 1 Hose Sizes