These cylinders were also known as the air cylinders. It is a mechanical device. This produces the force with the combination with the movements. This device gets power by the compressed gas. Pneumatic cylinders use compressed air to function properly. This device converts the potential energy of the compressed gas in the form of the kinetic energy. This is done by the compressed air which gets expand without any interference of the external energy input. The pressure which occurs because of such pressure is greater in compare with the atmospheric pressure.

In short, the whole process of pneumatic cylinders is based on the compressed air. This compressed air makes the cylinders working in the proper ways. When you look into the market there, you will find several different types of cylinders. They are mainly divided according to its size, functions or even according to its appearance too. They are designed in the fully specialized and specific functional ways. Have a look on some of the types this cylinder:
Single acting cylinders
This is mainly based on the force of air which is made in the single moving directions. The spring which is set in the cylinder helps in returning to its home position. Because of its working on a single direction, it gets its name of a single acting cylinder.
Double acting cylinders
In this types of cylinders, you will find that the force of air works on the both strokes that are on retract and extend strokes. In this cylinder, you will find two different ports to allow the air to get in. It gets in from the in stroke and gets out from the outstroke. It gets work on two different sections because of which it gets its name double acting cylinder.
These are mainly two types of the Pneumatic cylinders. These two are mainly two common types of the cylinders.   
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