Checks for Carbon Dioxide (CO2) concentrations Maintenance free dual wavelength NDIR (non-dispersive infrared) CO2 sensor CO2 measurement range: 0 to 6,000ppm Temperature measurement range: -4 to 140°F (-20 to 60°C) Humidity measurement range: 10 to 95%RH Continuous (20,000 sets) or Manual (99 sets) datalogging Complete with (6) AAA batteries, RS-232 cable, and Windows® 95/98/NT/2000/ME/XP compatible software