The valve's ductile iron disc is encapsulated with FKM material to create a tight seal. With the built-in O-ring seals no gaskets are required between mating flanges. The valve is easy to install but cannot be used as an isolation valve. Please refer to Chemtrol technical data sheets, valve selection guides and catalogs for engineering and installation information. PVC Schedule 80 exhibits excellent corrosion resistance properties and has the highest long-term hydrostatic strength of any othermore major thermoplastic material used for piping systems. Chemtrol® PVC valves are lightweight, easy to install, maintenance-free, and will not rust, scale, pit or corrode. Choose Chemtrol® valves for the most reliable, versatile and economical valve option in commercial and industrial applications. Chemtrol® valves are backed by a 1-year limited warranty. Because Chemtrol® is a NIBCO brand the flow-control valves are unsurpassed in quality, performance and longevity. less