Gas valves are flow control devices that control the flow of gases like liquefied petroleum, oxygen and natural gas. They come in a variety of ignition and valve types, as well as different coil voltage. Valve types include gas valves, flow control valves, furnace valves, fireplace valves and water heater valves. Valves are available in many styles such as ball, butterfly, plug, needle, and various check valve designs. They are used in many industrial, commercial and residential applications.