The Lennox 16Y31 Natural Gas Valve is a 3/4 inch x 3/4 inch control valve designed to regulate the flow of natural gas in residential and light commercial HVAC heating systems. It operates by opening and closing in response to electrical signals from the furnace control board, ensuring precise gas delivery to the burner assembly. https://www.partshnc.com/16y31-lennox-natural-gas-valve-34-x34