Decent hygrometer. What kind of replacement batteries does it take?
I got one of these. And it's nothing short of junk!
Now I understand why these things sell for so little money, they're either junk or not robust. Ordered one, pulled the battery tag, placed it in my humi and everything seemed to be fine, for like four days. Then the display went dead. I even spent a few bucks on a new battery which was stupid 'cause it still wouldn't work. Unless you purchase 100 of these for $0.10 each, you're better off paying more for one that will last longer than it takes for your humidifier to re-adjust the RH after you open the lid and drop this inside.
The device reads a constant 50%RH regardless of where I put it. I could probably stick this thing in a cup of water and it would say 50%.
Just received it the other day. I pulled the plastic tab that activated the battery and unit. It works great. It's amazing how well. When I open my humi to pull out a stick, the unit is already changing values. Very sensitive and with expensive cigars, it helps me relax.