This 2½” Sch 80 PVC Pneumatic Butterfly Valve, VITON, Double Acting, (FLANGE x FLANGE) is a butterfly valve with a pneumatic actuator on top for automatic control when compressed air is applied. the pneumatic actuator opens and closes when compressed air is applied to the respective ports. Butterfly valves are installed between a pair of flanges with falnge bolts. No gaskets are required, they are built into the valve face. Sch 80 PVC is robust and durable, perfect for commercial and industrial applications. VITON seals provide increased temperature resistance than EPDM seals and recommended for exposure to oils, gasoline and aggressive chemicals. Petram PVC supply has a huge inventory of Sch 80 PVC and CPVC parts.