Checks for Carbon Dioxide concentrations using a maintenance-free dual wave NDIR (non-dispersive infrared) CO2 sensor with a range of 0 to 6,000ppm. It can automatically datalog up to 20,000 data sets or you can manually enter up to 99 sets for later recall. Additional features include: Auto Power Off, Data Hold, Max/Min with time stamp, and Alarm. Comes complete with six AAA batteries, Windows 95/98/NT/2000/ME/XP compatible software, and an RS-232 interface cable.