I need a few good hygrometers

[Volt]

OK, how hard can it really be to measure the RH of a small box. I have done the salt calibration so many times I'm sick of it. I have 4 of the small black digital ones that are sold by every body under a variety of names. I really don't care what they measure, you calibrate, mark the diff it's off, and walla, you would think your done.

So if one is 7 points off and one is 3 points off I don't care. What I do care is that they don't seem to hold to how much they are off. Of the 4, one is adjustable. That's nice, I can get it set on 70%, but again it seems like I have to calibrate every 3 months or so. The batteries all got changed out 9 months ago to eliminate that as a problem.

I am ready to spend a few $$$ on some that are maybe of a better caliber. It might be I am getting what I am not paying for. The smokes are fine, mostly because I check them a lot. I can't imagine what you guys do with more than a few hundred sticks. Any recommendations?