FEBCO 1312 3/4" 860 Small Diameter Reduced Pressure Zone Backflow Preventer Assembly with Quarter Turn Ball Shut-Off Valve No Unions. This 3/4 inch 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 it 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, top mounted test cocks, spring loaded check valves, and a pressure differential relief valve.