Product review (5 stars): Works great.
Big LCD numbers that can be read across the room.
The one AAA battery lasts a long time (at least 2 years).
Has a nice color-coded "safe" range for humidity printed under the LCD (not on the LCD itself).

Another great thing is the humidity sensor updates every 3 seconds. You can put it anywhere inside/outside and and get an almost instant readout. Temperature seems to update slower, perhaps once a minute. Both temperature and humidity appear accurate when compared side-by-side with an analog meter.

Also has a button to switch temperature between F/C.

Get this. I realized my house was getting below 10% humidity in the winter thanks to my heater's humidifier not working. Now I know the perfect setting on my plug-in humidifier to keep my house around 40% RH. No more waking up with a bloody nose.