The Maxitrol 325-3-3/8 Gas Pressure Regulator 3/8" (10 PSI Max, 4–12" WC Out) is a high-performance regulator designed to maintain precise gas pressure for HVAC systems. It automatically reduces and stabilizes inlet pressure to ensure safe, efficient operation of furnaces, heaters, boilers, and other gas-fired equipment. https://www.partshnc.com/325-3-38-maxitrol-38-reg-10maxin-4-12-wcout