Round body air cylinders provide reliable and powerful transmission of linear force and motion with attachment points integrated into both ends. Double-acting round-body air cylinders interact with pressurized air to both extend and retract the actuator rod, allowing for motion control in both directions. Single-acting round-body air cylinders only convert air pressure to motion in one direction, then return to their natural position at rest. Mounting hardware for round-body air cylinders enhance the mounting possibilities and expand use of air cylinders. Replacement parts for round-body air cylinders replace worn or damaged components in compatible actuators.