Glentronics, Inc. CCV1 1-1/4 Inch to 1-1/2 Inch PHCC Pro Series Klunkless Check Valve Eliminates the irritating "clunk" when sump pumps turn off Patented silencing air chamber absorbs the shock Easily installed on both 1-1/4-Inch and 1-1/2-Inch pipes Includes 4 stainless steel hose clamps Designed for years of use