Wide Compatibility: Fits many common CO2 cylinders with conventional trapezoidal thread TR21-4. installed, you can also use previous versions of the CO2 Carbonator, compatible with the Soda Aerators DUO, Art and Terra. HIGH QUALITY MATERIAL: This CO2 adapter is made of strong and ultra-lightweight brass and aluminum alloy in high quality bright pink color, tightly sealed, -friendly, sturdy, high safety, rustproof and durable. EASY TO INSTALL: Press down on the pen and pull to easily remove the following pink part from the bottom of the soda machine. For DUO and ART carbonators, a small piece of housing must be cut in the cylinder to allow the cylinder to be inserted into the cylinder . SAVE MONEY: With this quick adapter, you can use your CO2 cylinders to use your new water carbonator. When you fill it yourself, you save the cost of replacing CO2 cylinders and improve your quality of life. Color: Red Material: copper+aluminum Package Contents: 1 x Fast adapter 2 x rubber band 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.