hit and miss hygrometer
I recently purchased 5 Mr. Misty Comfortmeter Indoor Hygrometer/Thermometers from Amazon.  While all 5 gave the same temperature (plus-minus 1F) only 3 of the 5 agreed on relative humidity (RH); the other 2 were off by at least 10%.  Amazon replaced one, but it was also off by 10% in RH. You wouldn't have known it unless you purchased several or had an independent RH meter.  Given that most people would use this at home, e.g., to keep the RH between 30 - 40% during winter, this product is really hit-and-miss when it comes to reliable accuracy.
Rating: 3 stars