QAD(W) Series Air Differential Pressure Switch The QAD(W) Series air differential pressure switch is an adjustable differential pressure monitoring switch designed to monitor over-pressure, vacuum, and differential pressure of air or other non-combustible, non-aggressive gases. Technical Specifications Measurement Media Air, non-combustible and non-aggressive gases Electrical Rating Resistance: Initial < 400 milliohmsCurrent: 1.5 A resistive (0.4 A inductive) 250 V Contact