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 systems 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. To install on the Terra Water Sprinkler, remove the pink piece from the bottom by pressing the pins as shown in the provided instructions and pulling the device downward. For compatibility with DUO and ART bubblers, a small section 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 does not screw into the CO2 cylinder valve, the cylinder is not compatible with this adapter. For any questions, support is available. 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 screw on the TR21-4 valve must face OUTWARD from the device, not sideways or inward. Why choose this adapter? Ideal for users who have a blue CO2 cylinder but want to avoid frequent refills or lack nearby refill stations. This improved quick adapter is designed for use with sparkling water makers and enables the use of compatible CO2 cylinders with TR21-4 threading on Terra, DUO, and Art series Sodastream machines. Scope of delivery: 1 x Quick Adapter