4 Pack Mini Digital Hygrometer Thermometer Gauge, Indoor Outdoor Temperature Humidity Meter for Greenhouse Humidors Incubators Reptile Terrarium Jars, Fahrenheit (℉) or Celsius(℃) (4)

I use these in all my animal enclosures where I have to measure temperature and humidity. I like that they're small and don't take up a ton of space. They're not great at re-sticking if you remove them, but you can always get more adhesive pads. They last a long time. Mine have been going for well over a year now and I've yet to change a single battery.

Works great - comes with battery installed and a set of backup ones. Can’t beat the value!

These were a perfect buy they are just big enough to read but not create an eyesore it does a quick job reading the humidity and temperature. The batteries came charged and ready to go and they work well with a constant wireless reading

I needed some hygrometers for a 3D filament enclosure that I was making and these came recommended by the designer of the enclosure I'm printing. I accidentally ordered 8 of them (only needed 4), but I'm keeping them because of the great customer service this company provided.While the hygrometers are great, providing both temperature (in C or F) and the humidity, it's the extras they provided that are over the top. I opened the package of 4 and saw that there were 4 batteries, that made sense, so I was prepared to open them up and install the batteries. Much to my surprise they all turned on when opened, so these are SPARE batteries, one for each unit! That's incredible. In addition they provided SIX double-sided tape discs for attaching them to a surface, so they even gave you TWO spares of those! Top notch!

Received as described and they are functioning as they should.

The cover on the back is very difficult to open. I used my nail at first,which brought out somevisible results - at 1 mm crack . But no further. A knife with multiple attempts finally pries it open, but at the price of the battery compartment cover flying over to the counter and into the cooked food on the counter. At the time, i was 3 feet away from the counter.Not the kind of effort i expected to put into opening a button-battery compartment. Poor design for sure

I bought several of these as I wanted something small enough to put in the plastic bags with my spools of 3D printing filament to monitor humidity. At this price I wasn’t sure if they would be very accurate but I was pleasantly surprised! As you can see from the photos, placing several in a bag with desiccant and then again beside each other out on the counter shows them all in near perfect agreement. They also arrive with an LR44 battery installed, and a spare LR44 for each meter. Note that these are designed to be mounted in a circular opening in a panel so the button that switches the temperature display between C and F is exposed and might get pressed accidentally if placed in a bag with other items. But I 3D printed some cases which made for a fun / easy project. Lastly, these update the display several times per minute and they respond to temperature and humidity changes within just a few minutes.

These work great around my 3D printing shop for monitoring humidity levels. They're cheap enough that I've taken to using them for making sure that humidity levels stay low in the sealed bins and even individual sealed bags I store my 3D filament in. Some have complained about their readings varying a lot, but the 8 I have so far all read within 2-3% of each other.THEY HAVE LONG "MEMORIES" THOUGH. I think this is why people complain about variations with them; it can take them a *long* time to settle down and read accurately if they've been exposed to extremes of humidity, especially on the low side.I've noticed that when I've had one of them in a filament bag with fresh dessicant (reading 10%, the lowest they go, maybe much lower than that), if I take it out and leave it in just room air, it can take days (and days!) for it to read the same as others that have been in the room air all along.If you have a unit that's "dried out" like this, put it in a baggie with a very lightly damp paper towel overnight, then let it sit in room air for a day and you'll probably find that it's agreeing with the others again.The same thing happens but to a lesser extent if they've been exposed to high humidity for a long time as well.If you let them sit long enough, they'll all eventually settle down to pretty close to the same values. I have a total of a dozen of these, bought over a period of more than a year, and they'll all agree with each other within a few percent if I'm just patient enough :-)