Compressed medical carbon dioxide (CO2) in a dedicated refillable container intended to be used for laparoscopic insufflation. The cylinder is filled with CO2 when delivered from the gas supplier and includes a valve stem, an opening/closing valve, and is graded according to size (capacity) and colour-coded to denote CO2 content. It is typically made of steel and must be used together with a pressure regulator in order to release the CO2 at the correct working pressure.