Product review (3 stars): ... show the same humidity and temperature reading which is good. However I have another different brand hygrometer and ...
I purchased 2 of these and they both show the same humidity and temperature reading which is good.  However I have another different brand hygrometer and these two units constantly have a 6 or 7% higher humidity reading.  The temperature readings are the same for all 3 units.  There is no way to tell which unit is showing the correct humidity reading, these 2 or the other 1.  I therefore just take the middle reading and as long as that remains  in the comfort level then I am satisfied.  Overall these are good value and give me acceptable (rough) humidity levels that is good enough for my purpose.