Good sealing performance, no air leakage when connected with the cylinder, more convenient to use. Mainly used for the thread adapter of the soda machine cylinder, and can also be used as an air source switch. Made of high-quality materials, high hardness, wear-resistant, long service life. The thread is tight, advanced manufacturing technology, stable performance, and installation and use are simple. Compatible with Sodastream TR21-4 soda bottles as an alternative to Quooker Cube bottles. Thread specification: TR21-4 female to TR12-3 male. Note: Due to production batches, slight variations in appearance or color may occur, which do not affect functionality. Color: As shown in photo. Material: Copper. Package includes: 1 x Soda CO2 Gas Converter. Other items shown in images are not included. Note: Color may vary slightly due to lighting and screen settings. Measurement tolerance: ±1–3 cm.