Product review (5 stars): Indoors Digital Humidity/Temperature Monitor, Grey and Black LCD Display, from IGADGITZ
This uses one AAA battery. It looks exactly like the Amazon photo.

Pro's:

1. Small footprint, takes up little space on a shelf or countertop. Has an included folding stand in rear.

2. Large digital display numbers are easy to read from a distance across a room.

3. includes a clock and calendar function. Choice of Celsius or Fahrenheit.

4. Battery is easy to install and change.

5. Simple design and inconspicuous looks, which I like.

6. This is accurate within a few degrees and % both for humidity and temperature.
However, both require at least 30 to 60 minutes to adjust and stabilize before you get an accurate reading.
If you move it across the house, don't expect instant accuracy in the new location, it has to 'settle in' first for up to an hour.

Con's (only one):

It was surprisingly difficult to set the F/C control, and some other settings, due to very poorly written instructions. Instructions need to be rewritten
for clarity. Also, you'll need those instructions again in future. I cut mine down in size, folded them and taped them to the back of the unit for future reference.

Overall I like this unit a lot. I've tried other competing units and they were junk. This one is reasonably accurate and much easier to read and operate.
Sample sent for testing and impartial review. This is one of only two temp/humidity gauges that I've tried and liked, out of a number of rejects.
The other model (without the clock/calendar feature) is from the same Seller, iGadgitz. Worth checking that one out, too.

I hope this is helpful as you comparison shop online.