Series 957RPDA, 957NRPDDA, 957ZRPDA Reduced Pressure Detector Assemblies prevent the reverse flow of fire protection system substances from being pumped or siphoned into the potable water supply. The 957RPDA incorporates a meter to detect ground leaks and unauthorized illegal taps, greatly reducing annual water expenses. It consists of a compact, stainless steel body with stainless steel internal parts, two check valves, a pressure-differential relief valve, shutoff valves, torsion spring checks and relief valve, and bronze, nickel-plated test cocks. Series 957RPDA, 957NRPDDA, 957ZRPDA is 70% lighter than traditional designs and is ideal for health hazard cross-connection, such as on fire sprinkler systems. Check with local water authorities for installation requirements. Maximum Working Pressure: 175psi (12.06 bar).