Product review (4 stars): Does the job
I bought two to keep in different areas but first I put them together in different spots within the house for comparison and 'calibration.'  The humidity usually ranged within 1-2 steps of each other and never more than 3 from each other.  Since I'm looking for 5% humidity ranges, that's within my tolerance.  Temp is usually the same or one off, never seen more than a two degree difference. Now one in bedroom and other in basement.