The Dwyer ADPS Series adjustable differential pressure switches are general-purpose, airflow-proving switches designed for HVAC and building automation applications. The ADPS Series can be used to sense positive, negative, or differential air pressure. The silicone diaphragm and calibration spring are housed in a rugged plastic enclosure with a removable cover protecting the set point adjustment knob and snap action switch terminals. Electrical connections are made through a 7/8 in diameter opening in the cover that accepts a 1/2 in conduit connection. Air sampling connections accept 1/4 in ID tubing.