Seat of Check Valve

This Backup Ring is made of Ductile Iron, and machined with high precision machining equipment. It has good physical and mechanical features. Afterwards the back-up ring will be lined with rubber material to form a 800S Check Valve seat. It gives enough support of the valve seat and guarantees the long-lasting use. 
Furthermore, the DI Backup Ring pays well in economy for 800S Check Valve.