Series 15M2 Water Hammer Arrestors are used in commercial and industrial applications to control water pressure shock and prevent water hammer conditions. They have a copper body, EPDM seals and O-rings, polypropylene piston, and NPT hex brass adapter end connections for easy installation. Series 15M2 is factory air charged and is not rechargeable. The sealed chamber prevents the loss of air to the water and ensures long and trouble-free life. It can be installed in new or existing plumbing systems, in concealed locations, with a standard pipe tee at any angle. Series 15M2 is ideal for commercial dishwashers, washing machines, and quick-closing faucets. ASSE and ANSI approved, PDI certified, and IAPMO listed. Maximum Working Pressure: 150psi (10.6 bar).