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 the air source switch. Made of high-quality materials, high hardness, and wear-, long service life. The thread is tight, superb technology, stable performance, and the installation and use method is simple. Color: Gold Material: copper Package Contents: 1X Thread Converts Adapter Female Tr21-4 to Male Tr21-3 Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.