Review on Precise Humidity Control With Xikar PuroTemp Round Digital Hygrometer, 10-Second Refresh Rate by Branden Type

I have 2 of these hygrometers now, and calibrated them both in the same "salt test" bag for 36 hours, then put them both in the same humidor. For about a week, they both read the same RH +/- 1%, but after that they started to drift apart by as much as 6%. The unfortunate truth is that it is nearly impossible to get a truly accurate hygrometer, so for that reason, this hygrometer is as good as any. The temperature reading is very accurate on both my units.Also, one reviewer pointed out that the big "calibrate" button is too easy to press on accident. If the reviewer had actually pressed the button (or read the instructions) before writing his review, he would have figured out that the "calibrate" button only works one time, then it becomes deactivated unless you remove the battery.