Series 4000B Reduced Pressure Zone Assemblies prevent the reverse flow of polluted water from entering into the potable water supply due to backsiphonage and or backpressure. It consists of bronze body construction, two, in-line independent check valves, replaceable check seats with an intermediate relief valve, and ball valve test cocks. Series 4000B is ideal for protection of health hazard cross-connections or for containment at the service line entrance. Check with local water authorities for installation requirements. Maximum Working Pressure: 175psi (12.06 bar).