Features [Brass Material] Brass has high strength, good plasticity, can withstand cold and hot pressure well, and has a long service life. [Suitable for low temperatures] Our adapter can be used several times at icy temperatures, making it more convenient to use. [Wide range of applications] The filling adapter can connect the bottle to any large CO2 tank, suitable for large gas tanks with or without residual pressure valve. [Excellent Filter Elements] Our adapters use upgraded filter material that eliminates the taste and smell of carbonated water for a better experience. [Good sealing performance] There is no air leakage when using this adapter to connect the cylinder, and the use is more assured. Specification: Item Type: CO2 bottle refill adapter Material: Brass Connector: CGA320 to TR21 4 Package list: 1 x CO2 Bottle Refill Adapter 1 x Hex Wrench 6 x large washer 9 x small washer 1 x socket 1instruction Small note: This adapter is not suitable for old cylinders (with pin cylinder valves) Package List 1 x CO2 Cylinder Refill Adapter 1 x Hex Wrench 6 x Big Washer 9 x Small Washer 1 x Plug 1 x Instruction