Reduced Pressure Zone Backflow Preventer Series Watts 957 Size 6 In. Connection Flanged Body Material Stainless Steel Body Iron Valves Temp Range 33 Degrees F Max Temp 140 Degrees F Max Pressure 175 psi Width 10-1/2 In. Length 50 In. Standards ASSE 1015 B64.5 FM Approved UL