Preset CO2 control at 1500 PPM. Built-in "self calibration" feature. Easiest to use CO2 Controller on the market. ETL listed for use in commercial applications. Simply plug in your CO2 generator or regulator and you are ready to go. Built-in photocell allows CO2 enrichment only during daylight hours. Durable powder-coated steel housing. 15 Amps/120 Volts/60 Hz. 3 year warranty.