Air cylinders convert compressed air into linear mechanical motion. Round-body air cylinders are cylindrical with attachment points integrated into both ends. Tie-rod air cylinders have blocks capping each end, joined by threaded tie rods to keep them securely in place. Extruded air cylinders feature formed aluminum housings and meet NFPA or ISO standards. Compact air cylinders feature very short strokes and small exterior dimensions for limited spaces. Rodless air cylinders ride along the axis of a piston and carriage instead of extending and retracting an internal rod.