The PS-ADPSXXXXM Series are air flow switches. These devices are general-purpose airflow-proving switches de¬signed for HVAC and energy management applications. It may be used to sense positive, negative, or differential air pressure. The PS-ADPSXXXXM Series plated housing contains a diaphragm, a calibration spring and a snap-acting SPDT switch. The enclosure cover guards against accidental contact with the live switch terminal screws and the set point adjusting screw.