Disclosure: I'm using this as a forensic tool as my first exploration of this very nice thermometer.My new GE refrigerator consistently freezes vegetables and fruits in their appropriate places, while leaving my drinks much warmer than I like, having to have continually ramped up my thermostat setting inside.This marvelous little thing transmits just fine from behind the stainless steel shell of my refrigerator; all but the one with some wires on it of the pictures included are done from inside the closed doors of my refrigerator!I confirmed the magnetic qualities of the attachment by hanging/sticking it on a powder-coated steel tools caddy - the magnet holds it readily against that 1/4" slice of steel. However, it comes with a sticky backed 1.375x1.5 inch steel plate so you can hang it magnetically, wherever it's most convenient for you to see.You can not only have it talk to you, you can get alarms if needed, all within the Bluetooth connection conveniently provided with the QR-coded warranty registration. Setup is a breeze, and you have the choice of Celsius or Fahrenheit for your metrics (pardon the expression) for how warm or cold it is.If it's a critical event, such as a commercial cooling unit, getting an alarm for temperatures outside of the needed degrees range is a very good thing to have, indeed. Likewise humidity, for other applications.All in a 1.625x3x.75 inch/2.5x6.5x1.7 CM package.I love it. Once I solve my refrigerator's misbehavior, I'll use it in and out, for times when I want to know what the temperatures and humidity are in places otherwise challenging to measure.You need one of these!!PS: They come with 2 AAA batteries, with the usual plastic strip isolating the positive terminal; you have to pull it out before it will work.But they won't work long. It was less than a week before mine died. The subsequent batteries' lifetimes were longer than a week, but not much. I'd otherwise have given it 5 stars, but it's worth degrading the review stars. Have a couple of AAA batteries ready if you become accustomed to looking at the display, or, like mine, it's hidden and you look at the neat computer/phone interface. And expect to replace batteries often, if you refer to it as often as I did (past tense; I gave it away) - even stuck, via the convenient magnet, on the outside of the refrigerator (as a room temperature monitor .And about those AAAs? We get ours from Amazon ☺ Our latest 100 box (https://www.amazon.com/AmazonBasics-Performance-Alkaline-Batteries-100-Pack/dp/B01B8R6V2E) was about a quarter apiece. You can get them in quantities as little as 8 or a dozen (or 20 or 36) and they're the equal of the other more costly brands.Just sayin' ☺
