A pneumatic cylinder is a device that converts compressed air energy into mechanical motion, usually in the form of linear movement. They are used in various applications requiring automation, such as in industrial settings to power machinery, open and close valves, or move objects along production lines.

There are several types of pneumatic cylinders, including single-acting cylinders, double-acting cylinders, telescopic cylinders, and rotary cylinders. Single-acting cylinders use air pressure in one direction and a spring for return movement, whereas double-acting cylinders use air pressure in both directions, providing controlled extension and retraction.

The selection of a pneumatic cylinder depends on the specific requirements of the application, such as stroke length, load capacity, speed, and the type of movement needed (linear or rotary). It is also important to consider cylinder diameter, pressure requirements, and environmental factors like temperature or humidity to ensure optimal performance.