Product review (5 stars): This works great. I hung the transmitter in the garage
I had a humidity problem in my detached garage.  I run a dehumidifier in the garage, but wanted to monitor the humidity to know when to empty the tank.  This works great.  I hung the transmitter in the garage, away from the wall and windows.  It transmits thru a couple wood walls for a distance of about 50-60 feet.  It's been working well for about 4 months on the original batteries.  I can't really vouch for the accuracy of the humidity reading, but it seems to match the humidifier setting.  When the humidifier shuts down with a full tank, the humidity reading goes up 10-15%....  So, it's perfect for my needs.
The base unit and it's display are fairly large.  I can easily read it from across the room... if there is enough light.  Like many LCD displays, you need a decent amount of light to read it.