Product review (1 stars): Complete junk
I bought this item because I wanted to get the idea of the humidity in my basement. I thought I needed a humidifier but wasn't sure, so i wanted a ballpark figure so I could decide--not exact numbers, but a clearer idea. However, this couldn't even give me that much.

The temperature and humidity numbers for the main floor of the house seemed way off--too warm, too humid, even with the AC on. So I held the thermo-hygrometer pen up to the AC vent while it was blowing, where the air was definitely cool and certainly quite dry; the measurements were 75 degrees, 70% humidity.  That's over an AC vent with the air coming out full-blast.

Later in the day, it read 82 degrees and 76% percent humidity in the center of a nearby room--despite the air conditioning being on. I took it outside, where the air was quite a bit warmer and much more humid; the readings barely budged.

Useless.