Brass material: The adapter is made of high-quality brass with good wear resistance, ensuring durability and airtightness of the connection, suitable for long-term use. Easy installation: This cylinder thread conversion adapter requires alignment of the threaded connection before connecting the gas bottle. Tighten by hand first, then moderately with a wrench. Avoid over-tightening to prevent damage to the sealing ring. After installation, slowly open the gas source and check for leaks to ensure proper function. Working pressure range: The adapter supports a working pressure up to 3000 psi (207 bar), which exceeds the typical 100–120 psi required by home soda machines. It allows safe and stable control of high-pressure gas within recommended limits. Thread size: 1 x thread conversion adapter (TR21-4 female to TR21-3 male). Enables compatibility between TR21-4 threaded bottles and Quooker Cube systems. Please verify thread specifications before purchase. Wide application: This CO2 brass cylinder adapter fits most TR2 standard CO2 bottles available on the market (verify bottle thread type prior to use). Ideal for Quooker Cube users and suitable for outdoor use due to its compact design. Color: Yellow & Red Material: Metal Package contents: 1 x connector with cap Note: Light reflection and display differences may cause slight variations in color appearance. Measurement may vary by +/- 1–3 cm.