Material: Aluminum alloy, Copper Color: Gold; Lilac Silver Thread Type: 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, suitable for bottles up to 60 liters and containing up to 425g of CO2 - Constructed from durable, lightweight aluminum alloy and copper components - Environmentally friendly, robust, corrosion-resistant, safe, and long-lasting - Designed to fit securely on 425g CO2 cylinders, including those from various brands such as Crystal 2.0, Penguin, Cool, and Aqvia - Includes a flat seal for secure connection when screwed onto the TR21-4 valve - For use with Terra models: Remove the pink piece from the bottom of the water dispenser by pressing the pins as shown in the instructions and pulling the unit downward - When using with DUO or ART models, minor modification may be required—remove a small section of the housing in the cylinder compartment to allow proper insertion - Insert the 425g cylinder into your Soda DUO, Art, or Terra machine and secure it by lowering the quick-release lever and pressing until it clicks into place - Important: Position the hexagonal screw (safety valve) of the TR21-4 valve so that it faces outward from the device, not sideways or inward toward the housing - If the adapter does not screw into the CO2 cylinder valve, the cylinder is not compatible - Customer support available for compatibility inquiries Why choose this adapter? Ideal for users who own blue CO2 cylinders but wish to use them with pink-threaded soda machines. Enables direct refilling of compatible blue cylinders and use with Terra, Duo, and Art series Sodastream machines via simple adapter attachment Package Includes: 1 x Quick Adapter