Air pressure, vacuum or a combination of both (differential) acts on a diaphragm which, in turn, actuates the nicroswitch. The design of the switch is such that the internal volume of air required is minimum. This allows the switch to actuate with very little air displacement, and actuation occurs without delay.
For best results the switches should be mounted with the diaphragm in a vertical plane with the microswitch facing up.
Switch can be supplied to meet Military Specifications.