COMPATIBILITY: The CO2 Soda adapter is compatible with DUO, ART, and TERRA, and fits standard CO2 bottles with traditional TR21-4 trapezoidal threads. Accommodates up to 60L and 425g CO2 bottles, you can continue to use traditional CO2 bottles and drink soda now. After installation, you can now also use CO2 cylinders from previous versions. Upgraded CO2 adapter, easy to install, you don't need to disassemble the carbonation machine, whether it's a duo, art, or terra model. You no longer have to worry about damaging the machine. This CO2 adapter is made of strong and ultra-light aluminum alloy, tightly sealed, environmentally friendly, strong, high safety, rust-proof, and durable. Economical: With this quick adapter, you can use your carbon dioxide cylinder to use your new carbonation machine. After installation, you can now also use CO2 cylinders from previous versions.