Active Air 20 lb CO2 TankDescription Large CO2 Storage: Our 20 pound all aluminum CO2 tank lets you store a considerable supply of carbon dioxide in a safe, transportable container. Note, the tanks are sold empty and they measure 23. 2" in height. Their slender design ensures minimal space occupancy in your indoor growing area. Premium Quality CO2 Tanks: Our CO2 tanks are composed of a high strength aluminum alloy. This makes them lighter than steel tanks and guarantees