Check the listing for details. Complete Aquarium CO2 System, Desktop CO2 Regulator with 45g Disposable CO2 C.... Condition: New. Listed at 92.98 USD. [Check the inner wall for seals before installation]. Easy Setup:Disposable CO2 cylinders require no frequent refilling, making installation quick and low maintenance. Quick-connect feature allows for instant installation of CO2 tubing, without the need to rotate the tubing - installation is completed in seconds.