The Hubbell Industrial Controls 69HAU3 is a pressure switch designed to control pressure levels in HVAC and air compressor systems. With cut-in at 15 PSI and cut-out at 50 PSI, plus adjustable operating ranges between 30–40 PSI and 7–15 PSI differential, this switch monitors system pressure and opens or closes electrical contacts to maintain safe, accurate operation. https://www.partshnc.com/69hau3-hubbell-industrial-controls-switch15ci50co30-40set7-15