Soda CO2 Gas Converter Adapter for Tr21-4 Female to Tr21-3 Male Thread for Quooker Cube Tank Output – Copper Good sealing performance, no air leakage when connected with the cylinder, more convenient to use. Mainly used as a thread adapter for soda machine cylinders and can also be used as an air source switch. Made of high-quality copper material, high hardness, wear-resistant, long service life. Tight thread fit, excellent craftsmanship, stable performance, simple installation and use. Allows the use of a sodastream TR21-4 soda bottle in place of a Quooker Cube bottle. Threads: Tr21-4 female to Tr21-3 male. Note: Product may vary slightly between batches; minor differences in appearance or color may occur but do not affect functionality. Color: As shown in photo Material: Copper Package Includes: 1 x Soda CO2 Gas Converter Adapter (Other items not included) Note: Light reflection and different displays may cause slight color variations between the image and actual item. Measurement error allowed within +/- 1-3 cm.