Prevent backflow in your irrigation system with the PVC Spring Check Valve, 1-1/4 in. IPS S X S in white. Water flows one-way through pipe when the water pressure is greater than the weight of the 2 lb spring. This easy-fit valve connects two 1-1/4 in. pipes in an irrigation or other pressurized system and prevents the backflow of water. Prevents costly property damage, pipe corrosion, and system issues. Durable check valve is made of PVC plastic. Pressurized Spring is made of stainless steel. Gasket is made of EPDM. Use fittings and other valves to set up a new irrigation system, expand an existing system, or make repairs.