Removes Water from Water Lines: Aids in the removal of water from your water lines and eliminates the need to use expensive antifreeze; For use with an air compressorA Great Winterization Tool: Ideal for boats, RVs and sprinkler systemsIncludes: A flexible hose with ball valve and durable brass fittingsBall Valve: Allows you to control the air flow rateThread Size: 3/4-11 1/2 NH male garden hose thread connects to a standard garden hoseEasy to Use: Simply attach the barbed fitting to the air compressor quick connect hose and the 3/4-11 1/2 NH male garden hose fitting to your RV or boat's city water inlet