The Oatey 34465 Quiet Pipes Water Hammer Arrestor is a plumbing device designed to prevent water hammer by absorbing shock waves and noise caused by sudden changes in water flow from quick-closing valves in residential and commercial applications. This lead-free arrestor features a copper body with a polypropylene piston and two NBR O-rings. It provides a 3/8 inch OD (Outside Diameter) compression inlet and a 3/8 inch female compression outlet, configured as a tee. With an AA arrestor size, it operates effectively within a temperature range of 33° to 180°F and a maximum working pressure of 60 PSI. The unit has a 0.875 inch body diameter and an overall height of 2.75 inches. It meets ANSI/ASSE 1010-2004 standards and is cUPC listed, allowing for installation at any angle, including in sealed walls without requiring an access pane