The Honeywell A.J. Antunes JD-2-GREY Pressure Switch is a critical component used in HVAC systems for accurate pressure management. This switch monitors and controls pressure differentials to provide maximum performance and safety within a pressure range of 0.1 to 4 inches of water column. https://www.partshnc.com/jd-2-grey-aj-antunes-1-4-wc-dif-vac-press-sw