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 the air source switch. Made of high-quality materials, high hardness, wear-resistant, long service life. The thread is tight, advanced technology, stable performance, and the installation and use is simple. Compatible with sodasteam TR21-4 soda bottles as an alternative to Quooker Cube bottles. Threads: Tr21-4 female to Tr12-3 male. Product may vary slightly between batches; minor differences in appearance or color do not affect functionality. Color: as shown in photo. Material: copper. Package includes: 1 x Soda CO2 Gas Converter. Light reflection and different displays may cause slight variations in color. Measurement error allowance: +/- 1-3 cm.