Features: This co2 regulator is the perfect accessory to connect a CO2 cylinder adapter to your existing aquarium fish CO2 tank regulator or Homebrew beer barrels mini controller. Internal thread TR21-4 to external thread W21.8-14 cylinder adapter. Made of quality metal material, it has a high hardness, is not easy to damage, durable and has a long service life. Small and lightweight, easy to carry and store, convenient to use. This is not recommended for carbonisation but is perfect for dispensing. Take your hobby to the next level with this versatile adapter. It'ssuitable for different devices, making it an essential tool for any setups. Specifications: Material: Metal Size: As Shown in the Picture Package Includes: 1x CO2 Regulator note: Please allow 1-2cm errors due to manual measurement. Due to the difference between different monitors, the picture may not reflect the actual color of the item.