Reduced Pressure Zone Backflow Preventer Series Watts 957 Size 4 in Connection Flanged Body Material 304 Stainless Steel Temp Range 33 Degrees to 110 Degrees F Max Temp 110 Degrees F Max Pressure 175 psi Width 22 3/4 in Length 31 11/16 in Features Outside Stem and Yoke Standards ASSE 1013 CSA B64.4 CUL FM