Item features: 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 Properties: Fits common CO2 cylinders with standard trapezoidal TR21-4 thread, compatible with bottles up to 60 liters and 425g CO2 content. Made of durable, lightweight aluminum alloy. 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 unit 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, securely onto the standard TR21-4 valve. Compatible with 425g CO2 cylinders, including those from various brands. IMPORTANT: If the adapter does not screw 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 safety valve on the TR21-4 cylinder must face OUTWARD from the device, not sideways or inward. Why choose this product? Ideal solution for users who have a blue CO2 cylinder but limited access to refill stations. This upgraded quick adapter allows direct refilling of compatible blue CO2 cylinders and enables use with Terra, Duo, and Art series soda machines. Package includes: 1 x Quick Adapter