As part of my pre-SCHIP cigar acquisition program I also bought a couple of inexpensive humidors through eBay.  They came with analog hygrometers but I decided that I would add a digital one to each humidor that also included a thermometer, since you have to maintain both humidity and temperature for optimal cigar storage.

I ordered two of the Western Humidor Caliber III units and they arrived today.  Analog hygrometers usually require calibration and there are a number of methods that usually involve water, salt, and plastic bags.  This digital one, though, does not require calibration and it had the following warning on the sheet that accompanied it:

WARNING:  This is an electronic instrument.  To maintain the warranty of this product and enjoy many years of error free operation, do not attempt to perform the following; DO NOT wrap this gauge in a wet towel to test the accuracy.  DO NOT attempt to perform the salt test.  DO NOT submerge the gauge in water!  DO NOT microwave or insert in an oven.  Should anyone suggest any of the above to test the accuracy of the CALIBER III ™, we recommend that you run from them immediately!  If you need help to any questions, please call us directly…

I have to give credit to the folks at Western Humidor for making my day with this product warning.