Material: Aluminum alloy, Copper Color: Gold; Lilac Silver Thread: TR21-4 Function: Connects CO2 cylinders with TR21-4 thread to DUO, TERRA, and ART soda machines with quick-connect cylinder system Features: - Compatible with common CO2 cylinders featuring standard trapezoidal TR21-4 thread, suitable for bottles up to 60 liters and 425g CO2 content - Constructed from durable, lightweight aluminum alloy and copper for long-lasting performance - Environmentally friendly, robust, corrosion-resistant, and designed for high safety standards - Ensures secure connection between cylinder and soda machine for reliable carbonation Compatibility and Installation: - Designed to fit 425g CO2 cylinders, including those from various brands such as Crystal 2.0, Penguin, Cool, and Aqvia - To install, screw the adapter firmly onto the TR21-4 valve using the included flat seal - For use with Terra models, remove the pink component from the bottom of the water dispenser by pressing the pins as shown in the 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 the soda machine and secure by pulling down the quick-release lever until it clicks into place - Important: The hexagonal safety valve on the TR21-4 must face outward, not sideways or inward, for correct operation Note: If the adapter does not screw onto the CO2 cylinder valve, the cylinder is not compatible with this product Why choose this adapter? Ideal for users who want to reuse or refill compatible CO2 cylinders at home, reducing the need for frequent replacements or trips to refill stations Package Includes: 1 x Quick Adapter