The Dungs Air Pressure Switch is factory adjustable, compact pressure switches for automatic burner controls. AA...A1 differential pressure switches are suitable for making/breaking a circuit when the medium pressure changes relative to the set point. Not suitable for natural gas, propane, butane, and other combustible gases. Can be used as a pressure, vacuum or differential pressure switch for air and non-aggressive gases. This specific air pressure switch has 12" to 60" W.C.