The HCS-3 system comes with an MBS-PRO 4-in-1 sensor to measure temperature, humidity, CO2 ppm, and the presence of light. Lighting control has never been easier or more capable. The optional MBS-PAR light sensor can be added to the system. It will automatically adjust light intensity to precisely provide the exact amount of illumination for optimum plant growth. The Hydro-X Plus has been can also track your DLI levels. Having 2 separate lighting control channels allows the user to create multiple lighting layouts (and dimming sequences) based on their individual preferences.