Function: The RV hot water drain valve is an accessory that interrupts the flow of water and prevents water from escaping. Size: RV water line cap for outer end tubing with 1/2 "outer fitting. Easy installation: no additional tools and hardware are required, and no industrial tape is required. Product material: made of high quality raw materials, waterproof and rust resistant, long service time. If you have any questions, please login to your Amazon buyer account to leave us a message, we will solve you as soon as possible.