Product review (1 stars): WARNING - not really Calibratable!
Although this Humidity Meter says you can calibrate it, the company does NOT offer a calibration kit for it, the RH300-CAL calibration kit will NOT work with this Humidity Meter Model #445815, i called the company.  The only meter that you can calibrate with the RH300-CAL calibration kit is the Model#445715!  This is very misleading and even the Extech company should NOT advertise this as calibratable if they don't make a compatible calibration kit.  I have to return it and buy the 445715 model in order to have the ability to calibrate.