This 10 IN lead free double check detector backflow preventer assembly prevents the backflow of pollutants that are objectionable but not toxic, from entering into the potable water supply. It is designed for non-health hazard applications and may be installed under continuous pressure service to protect against both backpressure and backsiphonage. It is used primarily on fire sprinkler lines when it is necessary to monitor unauthorized use of water and includes a gallons per minute meter that measures water flow. This assembly consists of two independently operating tri-link check valves, two shutoff valves, four test cocks, and UL/FM outside stem and yoke resilient seated gate valves. It features a compact stainless steel housing and sleeve that is 70 percent lighter than traditional designs. The maximum working pressure is 175 psi (12.06 bar).