Pneumatics rely on the power of compressed air. One of the best known pneumatic devices is the pneumatic hammer, or "jackhammer." A pneumatic hammer is powered by high-pressure air. Such air is delivered via a hose from an attached air compressor, which is a machine that increases the pressure of air from its normal atmospheric pressure to a higher pressure, by reducing its volume. The high pressure air drives a piston inside the hammer, much like the piston of an internal combustion engine but without the electric spark and internal explosion--an important safety factor in some explosive or wet environments.

Pneumatic devices are usually supplied with compressed air at about 90 psi (pounds per square inch), which equals 6.2 x 10⁵ Pascals; atmospheric pressure is 14.7 psi (1.01 x 10⁵ Pa). The jackhammer strikes the ground about 2,000 times per minute, delivering about 40,000 foot-pounds (54,000 J) of energy each minute.

An ordinary hand bellows was one...