Feature:1. SUITABLE MODELS: Male connector CO2 cylinder adapter is suitable for DUO, for TERRA, for Art soda makers.2. THREAD AND USE: The thread of our CO2 adapter is TR21 4 male thread which can be inserted after removing the base of the 60L CO2 cylinder, there are different usage methods depending on different cylinders, easy to install.3. POLISHED SURFACE AND GOOD SEALING: CO2 cylinder adapter has a well-polished surface and good sealing so that CO2 does not leak.4. EASY TO CARRY: The total weight of this CO2 connection for soda maker is light and very easy to carry, you can take the connection with you at all times.5. MADE OF BRASS AND ALUMINUM ALLOY: CO2 cylinder adapter is made of brass and aluminum alloy, resistant to corrosion, durable and safe.Specification:Item Type: CO2 AdapterMaterial: Brass, Aluminum AlloyThread: TR21 4 ThreadFunction: Connects TR21 4 threaded CO2 cylinders to for DUO, for TERRA, for Art soda makers that use gas cylinders. With this adapter, you can continue to use traditional CO2 cylinders with screw valves. The adapter can be used with 60L aluminum CO2 cylinders with screw valves.Package List:1 x Connector2 x WasherNote:When connecting the TR21 4 threaded CO2 bottle with the connector, if it turns out that the gas bottle cannot be inserted into the machine, it is necessary to remove the baffle at the bottom of the machine, so that the connector and the gas bottle can be inserted into the machine together.