Featuring a polished surface, good sealing, and anti-oxidation properties, the quick adapter offers corrosion resistance, durability, and safety. In just a few simple steps, your CO2 soda maker can be used with this quick adapter. This quick adapter allows soda devices to connect to older cylinders or other cylinders with TR21-4 Male Thread. It also enables connection of an old soda hose with TR21-4 Male Thread to Terra/Art/Duo models. It is made of high-quality copper and aluminum materials. The product measures 3.5 cm in length and 3.5 cm in height, with a caliber of 2 cm. Compatible with Soda DUO, Terra, and Art machines. Item Name: Quick CO2 Adapter Material: Copper, Aluminum Features: Easy Installation, Good Sealing, Anti-oxidation Size Details: L x H: 3.5 cm x 3.5 cm / 1.38" x 1.38" (Approx.) Caliber: 2 cm / 0.79" (Approx.) Notes: Due to differences in lighting and screen settings, the item's color may vary slightly from the images. Please allow slight dimensional differences due to manual measurement. Package Includes: 1 x Adapter 2 x Sealing Rings