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, supporting bottles up to 60 liters and 425g CO2 content - Constructed from durable, lightweight aluminum alloy and copper for long-lasting performance - Environmentally friendly, robust, corrosion-resistant, and designed for high safety standards - Ensures secure and easy connection to SodaStream DUO, TERRA, and ART models Instructions: 1. To install on the TERRA machine, remove the pink component from the base of the water dispenser by pressing the pins as shown in the included instructions and pulling the unit downward. For compatibility with DUO and ART models, minor modification may be required—remove a small section of the housing in the cylinder compartment to allow proper insertion of the cylinder. 2. Screw the quick adapter, with the flat seal inserted, firmly onto the TR21-4 valve. Fits 425g CO2 cylinders, including those from various brands such as Crystal 2.0, Penguin, Cool, and Aqvia. Note: If the adapter does not screw into the CO2 cylinder valve, the cylinder is not compatible. 3. Insert the 425g CO2 cylinder into your Soda DUO, ART, or TERRA machine. Secure it by lowering the quick-release lever and pressing the cylinder into the dispenser until it clicks into place. Important: The hexagonal safety valve on the TR21-4 cylinder must face outward, not sideways or inward toward the housing. Why Choose This Adapter? Ideal for users who own blue CO2 cylinders and want to use them with pink-thread-compatible soda machines. This adapter allows refilling of compatible blue cylinders and enables their use with Terra, Duo, and Art series Sodastream machines. Package Includes: 1 x Quick Adapter