A PVC shut-off valve is a type of valve used to control the flow of water or other liquids in a piping system. It is made of polyvinyl chloride (PVC), a durable and lightweight material that is resistant to corrosion and chemicals. PVC shut-off valves are available in a variety of sizes and can be used in both residential and commercial applications. They are typically used in conjunction with other plumbing fixtures, such as sinks, toilets, and washing machines.