This adapter is screwed on the gas cylinder, which is compatible with Sodastream. The adapter can easily and quickly connect the gas bottle and sparkling water making machine, which is easy to install and convenient. You can use it with confidence. Features -Color:Golden -Material:Brass -Size:4.20X3.20X3.20cm/1.65X1.26X1.26in -Made of high-grade material, which is and practical for use. -Suitable for Soda machine, air dispenser, inflatable converter, etc. You can also use this adapter to connect an old soda hose with TR21-4 external threads to a new soda machine. -It is a necessity for camping, BBQ, cooking, picnic, smoking and other outdoor activities when you need some sparkling water. -Well processing, it will not hurt your hands, easy to use and install, thus you can use it confidently. -Lightweight and portable, it is more convenient to store and use, bringing convenience to you. Package list: 1 x Adapter 1 x Wrench