The Atlas 9 is an easy to use digital CO2 controller with knobs to adjust your PPM set point and dead-band to operate your CO2 regulator or CO2 generator. The Atlas 9 has a 15Õ remote sensor that includes the photocell and CO2 sniffer. The photocell ensures daytime enrichment only. The Atlas 9 uses green LEDÕs to indicate the current PPM (Parts Per Million) levels. Plastic enclosure resists dust, rust and moisture. 15 Amps/120 Volts/60 Hz. 3 year warranty.