Soda CO2 Gas Converter Adapter for Tr21-4 Female to Tr21-3 Male Thread, Copper 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 connector. Made of high-quality copper material, high hardness, wear-resistant, long service life. The thread is tight, precision crafted, stable performance, and simple to install and use. Allows the use of a sodastream TR21-4 soda bottle with compatible systems requiring Tr21-3 connection. Threads: Tr21-4 female to Tr21-3 male. Note: Product may vary slightly between batches in appearance or color due to manufacturing updates; this does not affect functionality. Color: As shown in photo Material: Copper Package Contents: 1 x Soda CO2 Gas Converter Adapter Only the above package content is included; other items are not part of this sale. Note: Lighting and display differences may cause slight variations in color between the image and the actual item. Measurement error allowance is +/- 1-3 cm.