Straight Mini-Rester water hammer arrestor with 1/2" PEX crimp style connection (per ASTM F877/F1807). Effectively absorbs pressure surges to prevent damage to plumbing system. Installed upstream of any quick-shutting valves. Lead-free compliant, conforms to IPC-2009, certified by ASSE to the ANSI/ASSE 1010-2004 Standard.