Spring-Loaded Poppet Check Valves $54.00 - $140.00 Spring-Loaded Single Ball Check Valves $50.00 - $109.00 High Viscosity Ball Check Valves $92.00 - $179.00 1/2" Single Ball Stainless Steel Check Valve $117.00 1/2" Single Ball Alloy 20 Check Valve $194.00 1/2" Double Ball PVC Check Valve $99.00 3/8" Single Ball Stainless Steel Check Valve $92.00 3/8" Single Ball Alloy 20 Check Valve $146.00 3/8" Single Ball PVC Check Valve $117.00