Item features: 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 Properties: Fits common CO2 cylinders with standard trapezoidal TR21-4 thread, compatible with bottles up to 60 liters and 425g CO2. Made of durable, lightweight aluminum. Environmentally friendly, robust, safe, stainless, and long-lasting. Instructions: 1. Remove the pink piece from the bottom of the Terra water dispenser by pressing the pins as shown in the included instructions and pulling the device downward. For compatibility with DUO and ART models, a small portion of the housing in the cylinder compartment may need to be removed to allow proper insertion of the cylinder. 2. Screw the quick adapter, with the flat seal inserted, firmly onto the standard TR21-4 valve. Compatible with 425g CO2 cylinders, including those from various brands. IMPORTANT: If the adapter cannot be screwed into the CO2 cylinder valve, the cylinder is not compatible with this adapter. Contact customer support for assistance if needed. 3. Insert the 425g cylinder into your Soda DUO, Art, or Terra machine and secure it by lowering the quick-release lever and pressing the cylinder into place until it clicks. IMPORTANT: The hexagonal screw (safety valve) on the TR21-4 valve must face OUTWARD from the device, not sideways or inward. Why choose this product? Ideal solution when you have a CO2 cylinder but need a convenient way to connect it to your sparkling water maker. The improved quick adapter allows use of compatible CO2 cylinders with TR21-4 threading on DUO, TERRA, and ART series Sodastream machines. Scope of delivery: 1 x Quick Adapter