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, bottles up to 60 liters and 425g CO2. Made of sturdy and lightweight aluminum. Environmentally friendly, robust, high safety, stainless, and durable. 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 DUO and ART models, a small section of the housing in the cylinder compartment must be removed to allow the cylinder to be inserted. 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 other brands such as Crystal 2.0, Penguin, Cool, and Aqvia. Important: If the adapter cannot be screwed into the CO2 cylinder valve, the cylinder is not compatible with this adapter. 3. Insert the 425g cylinder into your Soda DUO, Art, or Terra machine and secure it by pulling down the quick-release lever and pressing the cylinder into the dispenser until it clicks into place. 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 blue CO2 cylinder but no access to a refill station. The upgraded quick adapter allows you to refill a blue CO2 bottle and use it with Terra, Duo, and Art series Sodastream machines. Scope of delivery: 1 x Quick Adapter