Short answers, pulled from the story.
A pneumatic cylinder is a mechanical device with compressed gas that moves a piston inside a sealed tube. Compressed air enters one end of the tube to push against the flat face of the disc-shaped piston, which transfers motion via an attached rod.
A single-acting cylinder has exactly one port for compressed air entry and uses a spring or gravity to return the rod when air exits. A double-acting cylinder uses two ports so both outstroke and instroke utilize the power of compressed air without relying on springs.
Telescoping cylinders nest a piston rod inside hollow stages of increasing diameter to allow notably longer strokes than a single-stage unit of the same collapsed length. Engineers primarily utilize these units where side loading remains minimal despite potential flexion risks.
Engineers treat a rod as a rigid body if its length stays under ten times its diameter but perform buckling calculations when the ratio exceeds ten-to-one. The effective cross-sectional area reduces instroke force because the piston rod occupies space inside the cylinder chamber.
Material choices range from nickel-plated brass to aluminum steel and stainless steel depending on load levels humidity temperature and specified stroke lengths. Tie rod cylinders remain the most common construction form proven safe for many loads while flanged-type cylinders appear more often in hydraulic systems.