Features BRASS MATERIAL - This CO2 refill adapter is made of brass, which is corrosion and wear resistant, and has great durability under continuous use. STANDARD SIZE: The cylinder adapter can be used for large CO2 tanks with CGA320 connector, which has standard size and great compatibility. MAIN PURPOSE: Allows you to fill CO2 from larger bulk cylinders into smaller cylinders for convenient use, easy to operate and greatly improve work efficiency. EASY TO INSTALL: With standard thread size, easy to screw into an empty CO2 gas cylinder and not easy to fall off when used, rust and wear resistant. WITH GASKET RINGS: Equipped with 4 large gasket rings and 5 small gasket rings, it has good sealing performance, no air leakage when connecting the cylinder. Specification: Item Type: CO2 Recharge Adapter Material: Brass Specification: TR21 4 to CGA320 Package List: 1 x Charging Adapter 4 x Large Gasket Rings 5 x Small Gasket Rings Package List 1 x Refill Adapter 4 x Large Gasket Rings 5 x Small Gasket Rings