1/2", Bronze, Hydronic Fill Valve Backflow Preventer Combo, Includes #9D Backflow Preventer & #1156F Feed Water Pressure Regulator In 1 Pre-Assembled Unit, Use In Commercial & Residential Hydronic Heating Systems To Provide Make Up Water To The Boiler & Prevent Backflow When Supply Pressure Falls Below System Pressure, All Bronze Body Construction Union Solder x NPT Connections, A High Capacity Fill Valve That Provides Quick System Filling & Purging, Maximum Pressure: 100 PSI, 6.9 Bar, Meet Lead Free Standards.