Compatibility: fits for many common CO2 cylinders that have the conventional trapezoidal TR21-4 thread, after installation, now you can also use CO2 cylinders from previous versions, compatible with water aerators DUO, Art and Terra. [High Quality Material]This CO2 adapter is made of a strong yet ultra-light brass and aluminium alloy for a tight seal, environmentally friendly, durable, high safety, rust-proof and durable. Easy to install: remove the following pink part from the bottom of the soda machine. (Press the pin to pull, easy to remove) For the DUO and ART carbonators a small piece of the housing must be cut out in the cylinder compartment so that the cylinder can be inserted into the compartment. Economical: With this quick adapter, you can use your CO2 cylinder to use your new water carbonator. Colour:Photo Color Material:Metal Package Contents: 1 x Adapter Only 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.