The Sioux Chief MiniRester residential water hammer arrester tee can be installed on washing machine supply valves or directly on washing machine tubs or shower tees. It comes in AA size and features a 0.75 inch female swivel hose thread connection. This washing machine water hammer has a brass finish. Water hammer occurs when the flow of moving water is suddenly stopped by a closing valve. If no measures are taken to control it, expensive fixtures and appliances within the plumbing system may become damaged. This can lead to fractured pipe joints, leaking valves, burst laundry hoses and premature failure of water heaters and other appliances.