Carbon Dioxide Regulator .5-15 Cubic Feet per Hour, C.A.P. You can connect the Carbon Dioxide Regulator to a bottled CO2 system to maintain optimum CO2 levels in their indoor garden. The Carbon Dioxide Regulator features an easy to adjust CO2 flow meter, pre-set regulator and solenoid valve. Included tubing allows even CO2 dispersion throughout the grow area when used in conjunction with an oscillating fan. Use the Carbon Dioxide Regulator with a digital CO2 controller or a timer for best results. Adjustable flow rate from .5 to 15 cubic feet per hour.