Co2 Refill Station Adapter for Soda Co2 Cylinder (TR21-4 Thread ) from CGA320 Large Co2 Tank Refill Station comes with 2000pis Gauge. Colour:As Shown Material:Metal How to use: 1. Screw the adapter onto the commercial CO2 cylinder 2. Screw the empty soda cylinder into the adapter 3. Open the valve of the large cylinder 4. After about 15-20 seconds, the cylinder is completely filled 5. Close the valve of the large cylinder 6. Open the exhaust screw to exhaust the remaining gas 7. Check the charging connector - done CGA320 connector: common in USA,CAN,Brazil,Colombia,Philippines,Mexico etc.. Note: Installation guide not included, we strongly recommend you professional installation. Please check as much as possible to make sure the item is what you need. Due to different product batches, the appearance , which does not affect the use Package Contents: 1 * Co2 Filling Station Refill Adapter Only the above package content, other products are not included. Note: Light reflection and