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 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, corrosion-resistant, safe, and reusable - Fits 425g CO2 cylinders, including those from various brands such as Crystal 2.0, Penguin, Cool, and Aqvia - Hexagonal safety valve (on TR21-4 cylinder) must face outward when installednever sideways or inward - For use with SodaStream Terra, DUO, and ART models; minor modification to cylinder housing may be required for proper fit Instructions: 1. Remove the pink component from the bottom of the Terra water dispenser by pressing the pins as shown in the included instructions and pulling the unit downward. 2. Screw the quick adapter (with included flat seal) securely onto the TR21-4 valve of the CO2 cylinder. 3. Insert the 425g CO2 cylinder into your soda machine and secure it by lowering the quick-release lever until it clicks into place. Note: If the adapter does not screw securely onto the CO2 cylinder valve, the cylinder is not compatible. Why choose this adapter? Ideal for users who want to reuse or refill standard blue CO2 cylinders and use them with compatible soda machines. This adapter enables convenient use of refilled cylinders with pink-threaded systems. Package Includes: 1 x Quick Adapter