Backflow Preventer, Dual Check Valve, .75-In.3 4", back flo preventer, dual check valve, use at drinking water supply service entrance or individual outlets, for non health hazard residential water system containment & continuous pressure applications, install vertically or horizontally, temperature range 33 to 180 degrees Fahrenheit, minimum working pressure 10 psi to maximum working pressure 150 psi, buna n seals & stainless steel springs, meets asse 1023 & csa b64. 6, wetted surface of this