FEBCO 825EBV70 1" N Pattern Reduced Pressure Zone Assembly Backflow Preventer with Quarter Turn Ball Shutoff Valve and Angle Union Connectors. This 1 inch N pattern bronze reduced pressure zone assembly backflow preventer is designed to prevent the reverse flow of high hazard (toxic) fluids found in the water from entering into the potable water supply due to back siphonage and or backpressure in accordance with national plumbing codes and water authority requirements. It is used in water services to industrial plants, hospitals, morgues, mortuaries, and chemical plants and is also used in irrigation systems, boiler feed, water lines and other installations requiring maximum protection. This compact integral assembly with an extremely short lay length provides versatility and simplifies new and retrofit installations which are advantageous in areas of limited space. This assembly consists of threaded quarter turn ball valves, test cocks, spring loaded Y pattern check valves, and one hydraulically dependent differential relief valve.