The XGC-1e Extreme Greenhouse Controller handles every aspect of an indoor garden, from the lighting to the exhaust to the supplemental CO2. The Complete Greenhouse Controller features a 24 hour time clock, 2 outlets for lights, 2 outlets for exhaust fans, thermostat and humistat for temperature and humidity control, 2 pump outlets controlled by a cycle timer and 2 outlets for supplemental CO2 controlled by a cycle timer. It is upgradable for PPM Co2 control at any time. It ensures that CO2 production turns off while the exhaust is on and at night. The Xtreme Greenhouse Controller is identical to the Complete Greenhouse Controller, except for the addition of Fuzzy Logic CO2 PPM control built in! Fuzzy Logic can be compared to a good driver. As a good driver approaches a red light, he or she applies the brakes to gradually slow down BEFORE getting to the intersection. Fuzzy Logic uses the same idea to keep the CO2 level at your desired setting, without going over the set point. 3 year no hassle warranty.