Intensity of suction, not quantity of air movement. The opposite of air pressure.

Suction-operated motor used for turning music rolls, or rarely for other devices. * Synonyms: air motor, wind motor.

Pump, usually containing bellows and a crankshaft, which supplies suction to operate a pneumatic system.

Box containing a set of valves, pouches, and associated parts of a pneumatic mechanism.

Device which controls the flow of air. Usually operated by a pouch, pneumatic, key or other mechanism.