PumpSpy's Silent Sump Pump Check Valve brings quiet operation and visibility to your sump pump system. This check valve is designed to allow maximum water flow from your pump. The clear valve body shows if water is moving and the pump works as designed. The spring-loaded flapper keeps the operation quiet, with no jarring water hammer noises. Our sump pump check valves are made with easy installation in mind and come with stainless steel clamps and Buna-N couplings that fit 1-1/2″ pipe. This sump pump check valve can quietly prevent water from being pumped twice and extend the life of a pump. Product Specs: Model: CV-150, 1 1/2 inch check valve, spring-loaded flapper Dimensions: 8.5 x 3 x 3 inches; Weight: 12.8 ounces.