Qty: 20 available. Spring check valves are placed on return line after steam trap. It prevents back flow of water into steam trap. It is spring loaded which makes sure the valve has closed. It provides a more positive seat then swing check. It is good on pump to boiler line where syphoning may be present. A Teflon disc is included. Available in a variety of sizes. All sizes have 200 WSP. FEATURES Spring loaded Prevents the back flow of water into the trap Bronze Durable Teflon disc is inc