Watts 3/4 in. D X 3/4 in. D Threaded Brass Double Check ValveSeries LF7R Lead free Dual Check Valves prevent the reverse flow of liquids in a plumbing system from entering the drinking water supply where there is a non health hazard. Designed for residential water system containment at the service entrance or individual outlets. They can be installed immediately downstream of the residential meter in a horizontal or vertical position. Replaceable compact plastic check modules. Available in a combination of