Soda CO2 Gas Converter Adapter for TR21-4 Female to TR21-3 Male Thread Copper Tank Output 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 materials, high hardness, wear-resistant, long service life. The thread is tight, precision crafted, stable performance, and the installation and use is simple. If you want to use a Sodastream TR21-4 soda bottle instead of a Quooker Cube bottle, this adapter is suitable. Threads: TR21-4 female to TR21-3 male. Note: The product may vary slightly between batches due to updates. Actual product may have minor differences or color variations, which do 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: Light reflection and different display settings may cause slight color differences between the image and the actual item. Measurement allowance is +/- 1-3 cm.