This 2½” Sch 80 PVC Swing Check Valve, VITON, (SOC x SOC) has a disk inside the swings open and closed to prevent flow in one direction using back pressure. Socket connections are joined to pipe of the same diameter with solvent welding. 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.