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 materials, high hardness, wear-resistant, long service life. The thread is tight, excellent craftsmanship, stable performance, and installation is simple. Allows use of a sodasteam TR21-4 soda bottle with compatible systems requiring Tr21-3 male connection. Threads: Tr21-4 female to Tr21-3 male. Tips: Product may vary slightly between batches; minor differences in appearance or color may occur, does not affect functionality. Color: As shown in photo Material: Copper Package Contents: 1 x Soda CO2 Gas Converter Adapter Note: Light reflection and different displays may cause slight color variations. Measurement error allowed within +/- 1-3 cm.