The Sensus Gas Division 496-20-1/2 1/2-inch Inlet Regulating Valve with a 1/4-inch orifice and green spring (6–14" WC) is a precision gas pressure control device designed for HVAC and commercial heating systems. It regulates incoming gas pressure to maintain consistent downstream flow for safe burner operation. https://www.partshnc.com/496-20-1-2-sensus-gas-division-sensus-gas-division-inlet-regulating-valve-1-2-w-orifice-1-4-green-6-14