Review on Extech RHM15 Mini Temp Indicator by Eric Basler

Poor calibration. Ordered from Revain and was intermittently in the lower part of the calibration range (reading 70% in a controlled environment of 75% RH), the rest of the time outside of the range (reading < 70% RH) . Revain replaced it without question, but the new device was even further out of range. These small units are NOT configured so you can adjust the relative humidity displayed like some other units. If you need to know what relative humidity is with any degree of accuracy, these are not the units for you. Extech believes +/- 5% is sufficient. If they made clocks with that level of accuracy, you could get clocks that could go forward or backward an hour and 12 minutes each day and they would be considered accurate. If you want to keep your humidor between 65-70% relative humidity. If it really is 60-65%, there will probably be a nasty surprise. And yes, I could mentally just add 5 or 6 or 7 or % to the reading, but I didn't pay the money for that. Avoid this unit if accuracy is important to you.