A.R.I. RP-501 Reduced Pressure Zone (RPZ) Backflow Preventer is a lead-free, UV-resistant composite plastic assembly designed to protect potable water systems from high-hazard back-siphonage or backpressure in commercial, industrial, and irrigation applications.

It features two independent, spring-loaded check valves, a hydraulically operated relief valve for enhanced safety, and four test cocks for easy testing.