Models 7515, 7525, 7545
+ Fast, accurate measurements in a single probe
+ Model 7515 measures carbon dioxide (CO2) only
+ Models 7525 and 7545 simultaneously measure
and data log CO2, temperature, and humidity and calculate % outside air
+ Model 7545 also measures
carbon monoxide (CO)
+ LogDat2 downloading software
included (except Model 7515)