Product review (5 stars): Simple Device That Displays Accurate Temperature, Relative Humidity
This VICKS HEALTHCHECK HUMIDITY AND TEMPERATURE MONITOR is a simple device that only does two things--display temperature (F. or C.) and relative humidity--but it does both really well.  The 3-1/2" x 3" monitor has a built-in stand, and a large, clear readout.  Beneath the display screen is a printed "key" that explains the ranges of relative humidity:  0% to 30% is too dry (dry eyes, nose & throat); 30% to 50% is the comfort zone (healthy breathing); and 50% to 85% is too humid for everyday (best for coughs & colds).

Out of the box, the monitor took a few hours to display the correct room temperature, but it now agrees with the changing readings displayed by a couple of other devices in the same room.  More importantly, the relative humidity display is totally consistent with the automatic  humidity settings on my new whole-room humidifier.  I purchased this monitor because I didn't completely trust the humidifier's automatic sensor, which is probably too close to a furnace vent.  Now this monitor tells me when the humidifier should be turned on or off.