Features: Made of premium metal material, which ensures the maximum durability. Professional manufacturing, high accuracy and not easy to break, anti-corrosion and wear resistance. Easy to screw empty CO2 cylinder into the adapter. Small size and lightweight, easy to use and store. Have one 1/8npt threaded port. Fits for 21*4 CO2 tank thread. Specification: Condition: Item Type: CO2 Refill Adapter Material: Metal Color: Black Size: Approx.6.3cm/2.5in Weight: Approx.68g/2.4oz Package List: 1 x CO2 Refill Adapter Note: 1. Because there was a manual measuring ,the size may has 1-2inch difference. 2. The color may be slight different due to the condition or light or different monitor.