This 3/4 inch Y pattern reduced pressure zone backflow preventer assembly 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 backsiphonage 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 assembly consists of a bronze body, threaded quarter turn ball valves, test cocks, spring loaded Y pattern check valves, and one hydraulically dependent differential relief valve.