Product review (3 stars): If you need something that will perform then spend more money and get good units which will last longer and you can adjust ...
Purchase four of these and not a one is accurate that I can tell.  Each show different humidity %'s and change without any accuracy. They are also short lived where two just stopped working all together after two weeks of use. Batteries are OK but unit no longer works.  If you need something that will perform then spend more money and get good units which will last longer and you can adjust for accuracy.  You get what you pay for!