12 Pack Pgzsy Mini Small Digital Electronic Temperature Humidity Meters Gauge Indoor Thermometer Hygrometer LCD Display Fahrenheit (℉) for Humidors, Greenhouse, Garden

On receipt, 11 of the 12 read 35% humidity and 1 read 12%. Pulled it apart, poked around, put it back together, and it read 40%, then settled to within a point of the rest within a day. It's worked fine since. No idea what taking it apart did, but if you get one that appears to be a dud but don't want to go through the hassle of returning the lot of them, it might be worth just taking it apart and putting it back together to see. No complaints otherwise. They're about as good as you can expect from a device this cheap, which is to say I wouldn't use them for anything too critical, but they do a good enough job at keeping tabs on my workshop. EDITED TO ADD: A few months later now, some of them do occasionally give weird readings, and tapping them on a hard surface makes them work normally again. It's a lot easier than taking them apart.

This is a good deal. If 10/12 worked I was going to be happy. Only one wasn’t and a quick readjustment of the battery fixed that. Yes, the batteries were already installed and working and of course we can say for how long. But if it bothers you, you can measure the button batteries with a battery meter and if depleted can take it up with Amazon/seller for refund/replacement. Or buy more button batteries, which would be needed eventually anyway. A combo takeout meal costs more than the whole original purchase. Yes, two or three varied up to 1 degree, but that’s pretty awesome if you look at the price; I use these for reference and comparison with my more expensive hygrometers. So I am quite happy!

Got these to keep an eye on filament storage conditions and they seem to work fine. Not happy about using with bags (they kinda get lost inside) but I got some containers and was able to fit these into the pour lids using a 3D printed adapter I designed. They are just exactly small enough to fit in the cap and snap in my adapters. They show humidity that seems to align with my expectations (new rolls or out of the dryer) so I have no reason to doubt them for now. The battery compartment cover seems to be mismarked--just insert the batteries (included) the same way up and it starts to work. Hoping for good battery life (LCD display) but TBD. 12-pack was less that $2 each so as long as they last a while (also TBD) that's a pretty good price. I only nicked a * because of unknown life--only using for a few weeks at this point. May update in future if I remember.

Arrived on time. All 12 are working and register both humidity and temperature within a degree or so of each other. Placed 10 in 1/2 gallon sealed jars that contain humidity/temp sensitive plant material. Would highly recommend these.

Seller was fast at getting the item to me. Item did have what appeared to be water damage staining on the box, but was not wet or deformed at the time of delivery, and the internal parts showed no obvious damage. I believe the packaging was wet at some point in the warehouse storage from FBA Warehouse, or the Manufacturer's storage. I use these hygrometers, as many others do, in 3D printing filament storage. When storing filament, the difference between 25% humidity and 35% humidity is the difference between needing to put your filament thru an 8 hour drying process and delaying printing of your model by that much time. So, if a sensor is wrong it could cost me a whole day of production, and possibly wind up irritating the customer that shipment of their anticipated item wasn't shipped out quickly. The numbers are large and readable. The temperature and humidity readings are quite quick to change - They update every 1-2 seconds. The issue that I have with these items are two-fold. 1. They aren't accurate to the actual humidity percentage -- and I'm not just saying that, I did several tests to confirm before choosing to not keep these as a reliable instrument in monitoring my storage solutions. 2. One of them repeatedly turned off when shaken or moved. Not sure how or why, but that's not a great sign! Once it was tapped gently on the table or given a soft shake, it would come right back on, which tells me it's not a battery voltage issue. Some of the readings weren't even close. Even between themselves, as a whole pack of 12, these sensors were showing a high degree of variance from one to the next. It wasn't anything crazy like 20% off, but it was 2-8% of variance between the lowest reading and the highest reading, while sitting within 18 inches of each other. I said I tested these in several ways, so i'll tell you now HOW -- Between taking photos for each test the item was allowed to sit in the environment for several hours to ensure that it wasn't reading something absurd like a fairly moist gust of air from a cough or something silly. No - these were tested in a manner that would be scientific. All within a reasonable distance of each other, in the same room, and in a room that had active air flow and no external factors like a pool, faucet, toilet, sink, or anything silly to throw off the readings. I have a hygrometer from another brand which reads several humidity points lower than the product that I received listed here. So, since they don't match up within 1-2% of each other, this product has failed that test. Next, I decided to put it against my Marathon Atomic Clock which has temperature and humidity sensors built in. The item listed here would show the temperature to be the same but the humidity reading was way off. So, it failed that test. I have an AMS with my 3D printer, which cost several hundred dollars; I trust the sensor in it WAY more than I do this little 10 cent sensor. I let them sit in this AMS box, which is a weather-sealed containment unit, meant to keep filament dry with the aid of desiccant media that absorbs moisture. They sat in the AMS unit for at least 8 hours before I took the photos you see. The AMS sensor would show 17%, while the on-screen display for this item was showing 20%. So, it failed that test. While it's not terribly inaccurate in that case, it showed a decent amount of variance that I wasn't too happy with it. If it wasn't for the other testing I had done, and the power reliability issue I have with a few, I would call that "good enough" to keep them. Lastly, I placed all the sensors in a bag a moisture-absorbing desiccant media, thinking that maybe (as a long shot) some of the sensors could be clouded by residual moisture inside their plastic clam-shell housing, for whatever reason. These things get manufactured in a place where it's known to be quite humid, and then shipped across the ocean... I wanted to give these every opportunity to succeed. If that meant spending a few hours letting them sit off to the side, in an effort to balance them to the environment, i was going to do it. I let them rest surrounded by moisture-absorbing beads for at least 4 hours. When I removed them, they were doing slightly better, but still not great. Immediately after removal they started reading the ambient air readings, which is good for me to see in terms of sensor responsiveness to air quality changes, but the readings were slightly off and varied across the 12 units i had, so it wasn't accurate. Fast but not accurate means nothing when I'm looking for the true number of the room. I don't care if it re-takes the reading only 1 time every 2 minutes or 1 time every 2 seconds. I need the reading to be accurate - and these were not. The value per unit is there, but you sacrifice quality to get more of an unreliable item. I would move on to another brand, if you actually care about getting a valid reading from your equipment.

Great product at a great price

these work as advertised... accuracy it within 5 units of humidity... which is more than I'd like, but workable. all arrived with battery tabs intact and all 12 worked. I actually bought 2 sets due to my large harvest. would recommend to anyone storing herbs or cigars.

4 venian sin servir y trabados… mala calidad

Pésimo artículo no tiene nada de precision la lectura cambia cada segundo y da saltos gigantes. Definitivamente pedire devolución

Use them for my Incubators and brooder boxes when I hatch out babies. Work perfect. Love the price and quantity.

Works good for what I bought it for, not exact. Expect up to 5 or so degrees of variance (+2.5/-2.5) in the units when sitting right next to each other.