The AFS is a general purpose airflow proving switch designed for HVAC, detection of blocked filters and fan suction, air flow monitoring in ducts, pipes, tunnels, and other energy management applications. It may be used to sense positive, negative or differential air pressure. Pressure Range: 0.05+/-0.02" W. C. To 12" W. C. Differential: 0.1+/-0.02" W. C. To 0.8" W. C. Electrical Rating: 300 VA pilot duty at 115-277VAC, 10amp, non-inductive, 277VAC, 60Hz Contact Arrangement: SPDT