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 with quick-connect cylinder system Features: - Compatible with common CO2 cylinders featuring standard trapezoidal TR21-4 thread, up to 60L capacity and 425g CO2 content - Constructed from durable, lightweight aluminum alloy and copper for long-lasting performance - Environmentally friendly, robust, safe, corrosion-resistant, and reusable - Designed to fit 425g CO2 cylinders; also compatible with select third-party cylinders including models from Crystal 2.0, Penguin, Cool, and Aqvia - Note: If the adapter cannot be securely screwed into the CO2 cylinder valve, the cylinder is not compatible - For installation on Terra models: Remove the pink component from the base by pressing the pins as shown in the instructions and pulling downward - For compatibility with DUO and ART models: A small section of the housing in the cylinder compartment may need to be removed to allow proper insertion - When installing the cylinder: Insert the 425g CO2 cylinder into the soda machine and secure by lowering the quick-release lever until it clicks into place - Important: The hexagonal safety valve (on TR21-4) must face outward from the device, not sideways or inward This adapter allows users to connect compatible refillable CO2 cylinders to their Sodastream DUO, TERRA, or ART series machines. Ideal for those seeking convenience and sustainability in carbonated beverage preparation. Package includes: 1 x Quick adapter