Brass material: The adapter is made of high-quality brass with good wear resistance, ensuring durability and airtightness for long-term use. Easy installation: This cylinder conversion adapter allows for simple connection. When connecting the gas bottle, align the threaded connection, tighten by hand, then moderately secure with a wrench without over-tightening to avoid damaging the sealing ring. After tightening, slowly open the gas source and check for leaks to ensure proper function. Working pressure range: Designed for cylinder thread conversion, this adapter supports a working pressure up to 3000 psi (207 bar), significantly higher than the typical 100120 psi required by home soda machines, ensuring safe and stable inflation under high-pressure conditions. Thread size: 1 x thread conversion adapter (TR21-4 female to TR21-3 male). Enables compatibility between TR21-4 threaded bottles and compatible systems. Please verify thread specifications before purchase. Wide application: This CO2 brass cylinder adapter fits most TR2 standard CO2 bottles available on the market (confirm bottle thread type before use) and serves as a practical accessory for compatible systems. Its compact design also makes it suitable for outdoor use. 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 error allowance is +/- 13 cm.