Ravands is the only brand of non-return valves on the market that is designed to provide a 100% leak-proof seal, ensuring that all of the water in your plumbing system remains inside the pipes. It is a threaded, three-inch valve that is made of durable polypropylene, and comes with an integrated non-return valve. This product is designed to replace your old, leaking valve and can be installed by a professional plumber in just minutes.