CO2 Aluminum Cylinder Supply Set - 0.5L - Stylish design brings additional elegance to your aquarium set up. CO2 diffuser provides clear accurate bubble reading and best diffusing effect. Seamless aluminum CO2 cylinder. Supporting base keeps CO2 cylinder in position avoiding any potential damage to the CO2 regulator. CO2 flow regulator provides constant and reliable CO2 dosing rate. Istas CO2 cylinders safety standards are approved by Technical Inspection Association (TUV).