The PVC True Union Swing Check Valve, 1 in. IPS U X U directs water flow one-way through pipe and prevents backflow. Water is conveyed one-way through the valve when the flap opens. This leak-resistant check valve connects two 1 in. pipes as a part of a complete irrigation or other pressurized system. Prevents costly property damage, pipe corrosion, and system issues. Durable check valve is made of PVC plastic. Flapper is made of EPDM. Use fittings and other valves to set up a new irrigation system, expand an existing system, or make repairs.