CO2 Quick Adapter for Duo quick Connect Qc, Art and Terra, Replacement for CO2 Cylinder Tr21 4 Male wall_mount_storage Color: Black Material: Plastic Package Color: Black Material: Plastic Package Contents: 1 * Remote Control Only the above package contents It can help you to make a round omelette perfectly Easy to install: One end of the quick adapter connects to the Duo water acidifier and the other end of the TR21 4 to the 60 liter CO2 bottle Efficient and economical: With this adapter you can continue to use your original CO2 cylinders and save yourself the hassle of changing in the store and the cost of replacing CO2 cylinders