Spec: Item Type: CO2 Adapter Material: Brass, Aluminum Alloy Thread: TR21 4 Thread Function: Connects TR21 4 thread soda cylinders to for DUO, for TERRA, for Art soda machines that use gas cylinders. With this adapter you can continue using traditional screw valve CO2 cylinders. How to Use: 1. Remove the CO2 cylinder and beverage bottle from your device.2. Screw the adapter (clockwise) onto the CO2 cylinder until a hissing sound is heard. Then turn the adapter (counterclockwise) back one part until the hissing stops.3. Turn the device upside down. There is a semi circular thin plastic bridge on the bottom of the device. The bridges are separated with small forceps. This allows the cylinder and adapter to be inserted first. Then turn the device back on.4. Remove the punch housing cover and tilt or lift the device slightly back.5. First insert the bottom end of the cylinder into the device, then insert the cylinder head into the cylinder seating. Then turn the cylinder so that the hex on the cylinder valve points in your direction.6. Press the lever. Place the device directly on the table.7. Replace the housing cover.8. Your CO2 cylinder is bubbling. packing list: 1 x Connector 2 x Washer