6-Pack Mini Hygrometer Indoor Humidity Meter, Mini Digital Thermometer Humidity Gauge Meter, Indoor Thermometer Hygrometer Monitor Fahrenheit (℉) for Reptile Thermostat, Jars Reptile, Fridge

Fast changing, extremely sensitive, and in tight sync on humidity. I bought 18, and placed then in a row across my work bench. After they settled in, they were within 1% of each other in a very interesting way... You could see waves of change, if one went up by 1%, usually it's neighbor would, and that would ripple across the line. Or there might be several waves sweaping from an end and the middle... It was interesting to see that they were all responding to the environment in sequence with the neighbor. This tells me they are quick responding and fairly sensitive.I am in an extremely dry environment, with humidity artificially increased by a swamp cooler, so I am testing the low end of the range, 20% to 30%. If your humidity dwells higher, you may get different results. These type of i9nstruments are more accurate at 75-85% than they are down where I use them, so accuracy is not pertinent in my use case, Instead I will be using these as a quality of storage indicator and alarm, so when I pull a roll of 3 year old nylon down, I can tell if it needs a 2 hour dry cycle or if it needs days more. A "freshness" indicator that I can read without opening the package.Humidity was within 1% of the units neighbor. However temperature was closer together, but the fractional degrees were all over the place... Most of the temperature sensors are closer than the humidity, but because the temperature scale is hundreds of points in either direction, the temperature looks like they are a little father apart, but really they are as close or closer than the RH%.The quality of the sensors are very high to all be in agreement, but these are too cheap to be calibrated, if that is important to yo, do some testing with a calibrated meter. I have a wet bulb and a calibrated meter in the shop, but like I said mine are not being used in a way for best accuracy, but these seem surprisingly high quality so I suspect accuracy is either very good, or at least very repeatable and consistent. These are the best I have tested so far.I will package these with sealed and dry filament, and the levels read will be wrong... Th

Why did you pick this product vs others?:A few months ago we bought a small 3D printer, but along with a printer you have to buy filament, and figure out a way to store it. Then there's the issue of moisture - too much and your 3D prints won't turn out well. I found these small hygrometers which work perfectly to put 1 in a bag or container with every roll of filament, to keep an eye on the humidity levels. These hygrometers may not be precise enough for scientific use, but for home uses they're fairly accurate and small, so they work great for our purpose.When they first arrived, we set them all on a table next to each other for about a day, to see if they all measured the same temp and humidity, there are slight variations but they all measured fairly close to the same so they seem accurate enough for our purposes. If I end up with any extras, I plan to also keep one at my desk at work since it's such a small item that takes up almost no space.

these are an economical way to monitor humidity in an enclosed container. I use it to monitor the relative humidty in the container where I store the 3D print filaments. I have found that they run about 3-5% different than the other monitors I have. I aim for 30% or less, so if they go to 20-25%, I know that I am sitting at 30% or slightly lower. If you are looking for a more precise % monitor, you might want to look at other brands.

These are great. We bought a used house with some ventilation issues, and bought several of these 6-packs of humidity/temperature sensors. We are able to tell where we have adequate ventilation and heating/cooling, and where we don't. I believe they are fairly accurate, though there is a bit of discrepancy among them if you leave them side by side. Sometimes the RH is off by 1-2 percentage points and the temperature is off by a degree or two, but for my purposes this is not a problem. I am quite pleased with these items.

Will update once I use them for a month… so far so good. 3/4% difference isn’t bad for most of my usages. Came out of the box already on, I like it.3 weeks later, working just fine. 3-4% differences. No worries in my book. Buying more here soon for jars.

These work great. I used double-sided tape and put them on the inside of my mason jars and was easily able to adjust temperature and humidity as needed

The temp/humidity sensors are fully functional and inexpensive, except the larger numbers are humidity, I wish the larger numbers were temp.

Bought these to use when curing herbs in quart size mason jars. They don't take up much room and are easily visible (contrary to the poorly lit picture). Cheers!