Please check your tank thread before placing an order. OD: 22mm W21.8-14 / DIN477 / M22-14 for your large CO2 tank. Commonly used in various regions. This item is designed to refill small CO2 tanks from larger tanks, allowing convenient and efficient refilling. CO2 Refilling Station Charging Adapter Type: W21.8-14 How it works: To use correctly, follow these instructions: 1. Cool the cylinder in the freezer for 1 hour. 2. Attach the CGA320/W21.8 connector to a standard CO2 gas cylinder. 3. Disconnect the quick connector of the black adapter, then securely tighten the black adapter to the cylinder. Ensure the knob on top of the black adapter is in the highest position. Do not press down the adjustment rod, as this may close the valve and prevent CO2 flow. 4. Reconnect the quick connector. 5. For most large cylinders, position the cylinder upside down or horizontally. 6. Slowly open the valve on the large gas cylinder. Opening too quickly may restrict flow. Open carefully until gas flow is heard. 7. After approximately 1520 seconds, the cylinder will be fully filled. 8. Close the valve on the large gas cylinder. 9. Open the bleed screw to release any remaining gas. 10. Unscrew the CO2 adapterrefilling is complete. Color: Black Material: Metal Package Contents: 1 x Charging Valve Connector Note: Light reflection and display settings may cause slight color variations between the image and the actual item. Measurement may vary by +/- 13 cm.