I bought two of the Radio Shack hygrometers at $23 a pop. They're model # 63-1036 and they are NON-adjustable. Just wanted to get that info out as I see them recommended here frequently. They no longer carry the adjustable type, this model replaces them. I've had it completely disassembled and there are no "pots" to tweak. And according to the infamous salt test, my analog is right on and this new digital is off +7%. So far I've only tested the one.