[FILLING YOUR CYLINDER]: It only takes a few minutes to fill the cylinder yourself . We provide additional rubber rings, which are made of food-grade materials, safe and reliable, they can a better sealing of the adapter. When old rubber ring aging, you can replace it.Compatible Model: The CO2 adapter only replacement for CGA320 to TR21-4( to CO2 tank with W21.8-14 joint)Easy to Install: The CO2 adapter connector kit is very easy to use, and the adapter is easy to tighten with empty CO2 cylinders.You can install it correctly according to our pictureQuality Assurance: High-quality materials have a longer service life and are .Good air tightness, no gas leakage when connected to the cylinder, more convenient to use.Color:Copper ColorMaterial:CopperPackage Contents:2 * Co2 Adapter Refills ConnectorOnly the above package content, other products are not included.Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.