Blueprint Controllers CGNG-4 CO2 Generator NG High Altitude, 4-burnerThe Blueprint Controllers CO2 Generator NG, CGNG 4 features four preinstalled brass burners that generate 10. 8 cubic feet per hour of CO2 using natural gas. The generator includes plugs to reduce the number of active burners, making it easy to reduce the CO2 and heat output to suit a smaller growing space. Electronic ignition and dual solenoid valves eliminate the open pilot flame and provide safe, reliable starts. A safety tip over switch