The Sofnolime 4 litre canister is designed to be used in a purpose built submarine manifold system to maintain a breathable atmosphere. It is highly volumetrically efficient: litres of CO2 absorption per litre storage, no maintenance, reliable operation, easy-to-use, watertight seals. 4 litre canister is available filled with Sofnolime 1550 or Sofnolime 1025 material soda lime