Product review (5 stars): Accurate
I purchased this because it was suggested by the Vicks humidifier I recently purchased for my bedroom.  While reading the instructions of the humidifier, it said to keep the humidity of the room between 40-60%, so I needed humidity monitor.  I set this monitor near my bed and it appears to be accurate.  The closer I set this monitor to the humidifier, the higher % it reads and further away, the lower % it reads.  The monitor uses a AAA battery but the monitor comes with a AAA already installed and requires the a plastic tab to be removed for it to work.  The battery is easy to replace via a plastic door at the bottom.  The temperature can be changed from Fahrenheit to Celsius by a small rubber push button on the back of the monitor.  The monitor is made to stand up by itself on a flat surface and does not have a wall mount option.  The overall quality build of this item feels cheap so I would not recommend dropping it.  Overall, the item works well and is simple and easy to use.