This Model RI-85 is a compact, lightweight portable CO2 monitor with an Infrared (NDIR) type sensor. This sensor provides fast and accurate detection of CO2 levels from 0 to 10,000 ppm. An internal pump is utilized for continual sampling, and the unit operated for 12 hours from one set of batteries. Microprocessor control provides average readings over a selected time period, and also can display the peak value detected.