The Extech 42280A temperature and humidity datalogger is designed to continuously monitor temperature and humidity to maintain ideal storage conditions in environments such as laboratories and cleanrooms, and to ensure comfort in hospitals and other indoor working facilities. The USB, included with the device, allows a user to connect the datalogger to their PC for further analysis. Users can then export to a PDF or Excel spreadsheet to see data and graphs on their PC.

The Extech 42280A has an internal sensor that measures humidity between 0 to 100% with an accuracy of ±3% and temperatures from -4 to 158°F (-20 to 70°C) with an accuracy of ±0.9°F (±0.5°C). The sensor also measures dew points from 32 to 122°F (0 to 50°C). Additional features include programmable audible and visual alarms, an LCD screen showing humidity, temperature, date, and time, as well as a wall, desktop, or tripod mount.

The logger stores 32,000 readings (16,000 per parameter). Logging intervals are selectable from 30 seconds to 24 hours. Optional calibration is available with 33% RH and 75% RH calibration bottles.