This 4 Inch Ames Deringer(Tm) 50G Reduced Pressure Detector Type II Backflow Preventer Assembly is Designed to Prevent Hazardous Contaminants And Non-Health Hazard Pollutants From Entering The Potable Water Supply System Caused by Backpressure And/Or Backsiphonage Conditions. Deringer 50G Features Inline Serviceable Os&Y Gate Valves, a Stainless Steel Body, And True-Seal(Tm) And Dual-Action(Tm) Checks For High Performance at Low-And High-Flow Rates. It May be Installed Under Continuous Pressure Service to Protect Against Both Backpressure And Backsiphonage. The Type II Bypass is Used to Monitor Unauthorized Water Usage, is Primarily Required on Fire Sprinkler Systems, And Comes With a Cfm Meter. Maximum Working Pressure is 175psi (12 Bar). | Apollo-Conbraco | D-4050G-CFM