The 8" 450DA Double Check Detector Backflow Assembly protects against both backsiphonage and backpressure on water lines in low health hazard, fire protection applications. Shaped in the n-Pattern, the 450DA is ideal for both new and retrofit installations in tight locations. It features an innovative metered bypass system to efficiently and effectively detect leaks and any unauthorized water use and the epoxy-coated ductile iron body protects against corrosion and utilizes the Zurn Wilkins Compound Check which provides low headloss.