This 1 inch stainless steel reduced pressure zone assembly is designed to prevent the flow of polluted 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 ideal for typical applications that are found in industrial plants, medical diagnostic equipment, reverse osmosis systems, carbonated beverage machines, brewing distillers, paper and pulp industries, chemical plants and aggressive atmospheres. This assembly consists of a 316 stainless steel body with NPT end connections, quarter turn ball valve shutoffs with tee handles, top mounted vandal resistant EZ-test cocks with covers, two in-line independent check valves, replaceable check seats, captured springs, corrosion resistant internal parts, and a hydraulically operated differential pressure internal relief valve for reduced space requirements.