2" Backflow Preventer, Double Check, Lead-Free Bronze with Ball Valves and SAE Test Cocks APOLLO 4ALF108A2F2" Backflow Preventer, Double Check, Lead Free Bronze with Ball Valves and SAE Test Cocks APOLLO 4ALF108A2F SPECIFICATIONS The Apollo Model DCLF4A Lead Free Double Check Valves A Series prevents contamination of the potable water supply due to back siphonage or backpressure from substances that are objectionable to the potable water supply, but non health hazards. The top accessed modular check valve cartridges provide captured springs, replaceable