EWPJDK Mini Hygrometer Indoor Humidity Meter Hygrometer Thermometers 4 Pack Humidity Meters Gauge Hygrometer Mini Digital Thermometer Hygrometer for Humidors, Greenhouse, Garden, Cellar (1)

Great little humidity meters. I put these in each of my printer filament cases to monitor the humidity. Also good to keep a bag of desiccant in the cases.

Great price. These let me track the percent humidity throughout my home to make sure it stays under 60% (the threshold for mold growth). These sensors are really great for getting the information you need for controlling home air quality. If you’re prone to respiratory illness, have asthma, live in a humid climate, or a home with questionable ventilation, buy these. I know these are mainly used for reptiles, but I found them extremely helpful for my own health as well as that of my pet. Apparently our home regularly stays at over 80% humidity throughout, swaying between the low 70s and high 90s % humidity. It means the air is permanently heavy and everything is slightly sticky. Humans generally should aim for the 40-50% range. For asthma, humidity between 30-40% is recommended. This sensor pack let us find out how our behaviors from shower temperature to closed/open windows affects the moisture in the home so we can aim for a healthier balance. It’s the most important tool for staying on top of mold/spores and bacteria in the air. Landed up purchasing a dehumidifier and these sensors are very accurate and in tune with the changes, even if they take a minute or two to adjust. I wish they had a small place for a hook or screw so I could hang them instead of having to find places to stand them up, but so far no complaints.

These are great little hygrometers. They aren't perfectly accurate but they're very close and usually have a margin of error around plus or minus 2%. I used them around the house when we were having issues with high humidity to pinpoint the most humid areas and manage it with a dehumidifier. I also used them in a small enclosed hydroponic set up I use to grow jalapenos. They're small and light which makes them really easy to hang on a wall or make a small cut out in plastic for. I learned that you shouldn't block the back of these as well as that is where the sensor reads the humidity from. There is a small array of holes on the back that you have to make sure have proper ventilation to get an accurate reading. The display is really easy to read and they function on one battery for ages. I haven't had to replace the battery in any of them and they've been going for about 5 months. Overall I would recommend these for the price and quantity and I'll probably get them again.

Great for my 3d printer filaments. accurate and lasts long. just pop it in and it works.

Like many others here, I'm not using these for gardening or preserving historic paintings in a controlled environment - no, no.. I'm using these to monitor the humidity levels around 3D printing filament. As simple and as silly as it may sound, raw filament does absorb moisture and will cause expansion and popping of the absorbed moisture when it is fed thru a several hundred degree heated print nozzle, leaving bad marks on the prints and unmelted plastic in the nozzle... So, to combat this, we use hygrometers, to monitor moisture content.. The devices that I received were all powered on and reading well. There was 1 or 2 that were out of sync with the rest of the group by a percent or two, so it's not extreme precision, but the work wonderfully enough to get a good read on what is happening in the environment. I say these get a passing grade from me. I appreciate their simple build, good looks, and efficient reads.

These are good, and seem to show values very close to instruments that cost far far more (that I have installed alongside) However, I consider these somewhat disposable. I have one on my trail bike that is accurate when it displays, but the display only works when the temp is below 54. Once it hits 55 the display simply disappears. I'd prefer it if the temp was the big digits and the humidity was the small, but that's a minor issue.

I have these everywhere. Cigars, bedrooms, guitar cases etc. Cheap and super handy!!

These are great! I like them for checking on plants, humidity during dry season etc