The GD-444 series of portable infrared monitors can measure carbon dioxide up to 10,000ppm, as well as temperature, relative humidity and toxic gas levels in the iaq version. The units come equipped with a backlit lcd display, built-in air pump, push-button controls, recorder output and battery charger. Also, the optional data log can store up to 1,000 readings along with time and date. CEA Instruments Inc., Emerson, N.J.