The 12 in 350DA Double Check Detector Backflow Assembly, with flanged end OS and Y gate valves, protects against back siphonage and backpressure in low health hazard, fire protection applications. Featuring a metered bypass system, the 350DA efficiently and effectively detects leaks and any unauthorized water use, saving you added costs associated with maintenance and repairs. The Zurn® Wilkins Compound Check provides low headloss, and backflow installation is approved in both horizontal and vertical positions.