Stop piping system from raising off ground with the PVC Low-profile Swing Check Valve, 2 in. IPS S X S, White. Water is conveyed one-way through the valve when the flap opens. This high-quality valve, flattened on one side, connects two 2 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 foot 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.