The Model AFS-305 is a general purpose proving switch designed to require manual reset following actuation. It can be used to sense positive, negative, or differential air pressure in HVAC and Energy Management applications that require operator interface. The plated housing contains a diaphragm, a calibration spring and a snap-acting SPDT switch. The AFS-305 has a field adjustable set point range of 0.25″ wc to 12.0″ wc. The screw terminals are protected by an enclosure that accepts two 1/2″ conduit connections. This switch has an SPDT manual reset contact arrangement. It is equipped with two compression ferrule and nut sample line connectors that accept ¼” OD rigid tubing.