Quick Connect CO2 Adapter Compatible with Sodastream Water Spritzer Duo Art, Terra, TR21-4 Material: Aluminum alloy, Copper Color: Gold, Lilac Silver Thread: TR21-4 Function: Connects CO2 cylinder with TR21-4 thread to DUO, TERRA, and ART soda machines with quick connection cylinder Features: - Fits many common CO2 cylinders with standard trapezoidal thread TR21-4, bottles up to 60 liters and 425g CO2 - Made of sturdy and lightweight aluminum alloy - Environmentally friendly, robust, high safety, stainless, and durable Instructions: 1. Remove the pink piece from the bottom of the Terra Water Spritzer by pressing the pins as shown in the supplied instructions and pulling the device out downwards. For compatibility with DUO and ART models, a small part of the housing may need to be removed in the cylinder compartment to allow insertion. 2. Screw the quick adapter with the included flat seal firmly onto the standard TR21-4 valve. Fits perfectly on 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 bottle valve, the cylinder is not compatible. 3. Insert the 425g cylinder into your Soda DUO, Art, or Terra and secure it as usual by pulling down the quick release lever and pressing into the water spritzer until it clicks into place. IMPORTANT: The hexagonal screw (safety valve) of the TR21-4 valve must face OUTWARD from the device, not sideways or inward. Why choose this adapter? Ideal solution when you have a blue CO2 cylinder but no access to refill stations. This improved quick adapter allows you to refill compatible CO2 bottles and use them with Terra, Duo, or Art series Sodastream soda machines. Package Includes: 1 x Quick Adapter