Material: Aluminum alloy, Copper Color: Gold; Lilac Silver Theme: TR21-4 Function: Connects CO2 cylinders with TR21-4 thread to DUO, TERRA, and ART soda machines using quick-connect cylinder system Features: - Compatible with common CO2 cylinders featuring standard trapezoidal TR21-4 thread, supporting bottles up to 60 liters and 425g CO2 content - Constructed from durable, lightweight aluminum alloy and copper for long-lasting performance - Environmentally friendly, robust, safe, rust-resistant, and built for durability - Fits securely on 425g CO2 cylinders, including those from various brands such as Crystal 2.0, Penguin, Cool, and Aqvia - Includes flat seal for secure connection; screw the adapter firmly onto the TR21-4 valve - Note: If the adapter does not screw into the CO2 cylinder valve, the cylinder is not compatible - For installation on Terra model, remove the pink component from the bottom by pressing the pins as shown in instructions and pulling downward - When using with DUO or ART models, minor modification may be required in the cylinder compartment to allow proper insertion - Insert the 425g cylinder into your Soda DUO, Art, or Terra machine and secure by engaging the quick-release lever until it clicks into place - Important: Position the hexagonal safety valve (on TR21-4) outward, not sideways or inward, for correct operation Why choose this adapter? Ideal for users who have a blue CO2 cylinder but want to avoid frequent refills or lack nearby refill stations. This upgraded quick adapter allows you to refill compatible CO2 cylinders and continue use with Terra, Duo, and Art series Sodastream machines. Package includes: 1 x Quick Adapter