This is a BRAND NEW OEM Lennox/Armstrong/Ducane Gas Furnace Air Pressure Switch. The Part # is 93W94 (also 103614-09 & 10361409 ) & the Honeywell # is 9371DO-BS-0036. It is rated at 0.90" W/C PF. Switch has 2 hose ports and 2 wiring terminals. Thanks for looking and good luck!
An air switch is safety designed to ensure that your inducer motor is running at the proper RPM, and creating the proper vacuum for your furnace to flue safely.