Watts 0555177 1" Lead Free Brass Silent Check Valve LF600 Series Maxi-Flo check valve is used in general industrial and plumbing applications to prevent the effects of water hammer in the piping system. It provides a silent operation with low pressure drop and can be installed horizontally or vertically. This valve consists of a lead free brass body, lead free brass check and adapter, conical lead free brass disc, PTFE seat and threaded end connections. The maximum working pressure rating is 400 psi (27.6 bar), WOG non-shock at minus 20 to 100 degrees F (minus 29 to 38 degrees C) and 15 psi (1 bar) WSP at 250 degrees F (121 degrees C).