Product review (5 stars): Great Value!
Simply put, this thermometer/hygrometer is a great value!  I was looking for an inexpensive hygrometer to monitor the humidity in multiple dry-food storage containers.  I first purchased a Caliber III and a Caliber IV humidor hygrometers due to their reputation for accuracy.  However, they are expensive, so I wanted to find a less expensive hygrometer to keep a hygrometer in each food container.

I purchased five units to test, and to compare to the more expensive Caliber hygrometers.  I was impressed with the five Amir Digital Thermometer/Hygrometers, and while the Caliber units seem to be superior, at approximately 1/3 the cost, I decided that the less expensive units satisfied my needs.

I purchased 15 additional units, but found five of them were defective.  One had a defective display, the other four failed to "turn on" after inserting the battery.  I managed to get three of the four to work after inserting a cardboard spacer on top of the battery, so the battery would be pushed slightly further into the battery compartment.  When Amir was informed of my experience, they offered to refund the cost of all five units!  I ordered five replacement units, and all five worked as intended.  I am very impressed with Amir's customer service!!!

As an indication of their accuracy, I tested 22 units standing together on a table.  All 22 show the same temperature, +/- 1 degree F.  As expected, the humidity readings aren't as consistent, but acceptable.  20 of the units show the same humidity, +/- 2 %.  The fact they read very close to one another does not prove accuracy, but it is a good sign of consistency.  As for the other two units, they are "outliers".  One unit shows a relative humidity 4% outside of the band of the 20, the second unit shows a relative humidity 7% outside the band of the 20.

Tips for getting the most accurate humidity readings.  The ambient air enters the back of the unit to reach the humidity sensor, so the back must be kept clear.  That means it shouldn't be hanging on a wall, nor laid flat on a surface.  It also takes much longer for the relative humidity to stabilize than for the temperature, so allow plenty of time for it to stabilize after moving it to a new location.  That is why I chose to keep a hygrometer in every storage container, so it remains in a stable state.

In summary, the Amir Digital Thermometer/Hygrometer is a great value!  If you happen to receive a defective unit, customer service will take care of it.  Customer Service is GREAT!