This 2 Inch Ames Deringer(Tm) 20 Double Check Valve Assembly is Designed to Prevent Non-Health Hazard Pollutants From Entering The Potable Water Supply System Caused by Backflow Due to Backpressure And/Or Backsiphonage Conditions. Deringer 20 Features Integral Eccentric-Seal(Tm) Butterfly Shutoff Valves For a Short Lay Length, Integrated Tamper Switches, And Dual-Action(Tm) Checks For High Performance at Low-And High-Flow Rates. This Valve Comes With Kit to Adapt Valve From 2 Inch to 2-1/2 Inch Size. The Kit Includes Two 2-1/2 Inch Grooved Couplings And Two 2 Inch Npt x 2-1/2 Inch Groove Adapters. End Connections Are Union Type Stainless Steel 2 Inch Female Npt Threads For Ease of Installation. It May be Installed Under Continuous Pressure Service to Protect Against Both Backpressure And Backsiphonage. Maximum Working Pressure is 175psi (12 Bar). | Apollo-Conbraco | D-2020K