Watts 0438048 - 4 In SS Reduced Pressure Zone Assembly Backflow PreventerThis 4 inch lead free reduced pressure zone assembly backflow preventer helps prevent the reverse flow of fire protection substances and water of non potable quality from being pumped or siphoned into the potable water supply due to backsiphonage and or backpressure in accordance with national plumbing codes and water authority requirements. Its compact modular design facilitates easy maintenance with a single access cover for in line repairs. It is