The TrolMaster Digital CO2 PPM Controller (BETA-8) CO2 controller offers a precision CO2 NDIR sensor / controller in an affordable easy-to-use package. The BETA-8 features a high-quality remote CO2 sensor (with 16ft cable) and built-in photocell to automatically activate your supplemental CO2 system to maintain CO2 PPM levels only during daylight hours. The BETA-8 also has adjustable deadband and min-max recall. It also has a ‘fuzzy-logic’ feature which will more accurately control compressed CO2 systems. The CO2 sensor can be easily re-calibrated and will continue to operate accurately for many years.