Good sealing performance, no air leakage when connected with the cylinder, more convenient to use. Mainly used for the thread adapter of the 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 for use with steam TR21-4 bottle instead of a Quooker Cube bottle. Threads: Tr21-4 female to Tr12-3 male. The product may vary slightly between batches; minor differences or color variations may occur but do not affect functionality. Color: as shown in photo. Material: copper. Package Contents: 1 x CO2 Gas Converter. Only the above package content is included; other products are not included. Light reflection and different displays may cause slight color differences between the image and the actual item. Measurement error allowed is +/- 1-3 cm.