TrolMaster Digital CO2 PPM Controller (BETA-8)TROLMASTER DIGITAL CO2 PPM CONTROLLER BETA8 The 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