Can be installed vertcally or horizontally. This 3/8 inch dual check valve prevents the reverse flow of polluted water from entering into the drinking water supply at the service entrance or at individual outlets. It is designed for in-line continuous pressure applications, such as wash-down sinks or other installations, where a hose type device connected to the domestic water supply can be submerged into a non-potable liquid. It consists of a chrome-nickel plated lead free brass body, 3/8 union NPT thread female inlet by NPT thread female outlet, two plastic replaceable check valves, Buna-N seals, silicone discs, and stainless steel springs. The minimum working pressure is 10 psi and the maximum working pressure is 150 psi Temperature range is 33 to 180 degrees F (0.5 to 82 degrees C) continuous