Use to easily blow out water lines before winter storage.Provides a simple way to remove water from plumbing systems before winter storage. Just screw into municipal water inlet and open all drains and faucets. Then connect an air pump to the Schrader valve and blow out the water. Plastic plumbing fitting with valve. Key FeaturesHelps clear the water lines in your boat during winterization and dewinterizationScrews in to boat's municipal water supply inletMakes winterizing your boat easyConnects to air pump (sold separately)