The 2-1/2" - 12" backflow preventer shall be an Apollo® model DCLF4A lead free double check valve. The TriForce™ center stem guided check valves shall feature reversible silicone rubber seat discs. the check valves shall be held in place by stainless steel snap-in retainers (2-1/2" - 6") or stainless steel studs & nuts (8" - 12"). access to the check valves shall be by an Apollo quick-connect stainless steel coupling (2-1/2" - 6") or grooved couplings (8" - 12"). the bodies shall be stainless steel in 2-1/2" - 8" sizes and FDA epoxy coated ductile iron in 10" & 12" sizes. The lead free Apollo ball valve test cocks shall have stainless steel handles. the assembly shall prevent contamination of the potable water supply due to back-siphonage or backpressure from substances that are non-health hazards. The pressure drop across the assembly shall be documented by ASSE or USC FCCC&HR approval curves.