Bought a new fridge and couldn't get the right temps. This thing allowed me to get temperatures dialed in to the sweet spot. So handy it's still being used. Mine has been fine using alkaline batteries. Best recommendation.

I use this for two seperate freezers. One is in the basement directly below the receiver/monitor, no more than ten feet away, through an insulated wood floor, no connectivity issues. The other is approximately fifteen feet away through three interior walls that contain electrical but no plumbing, again no connectivity issues. I have not calibrated these but they appear to be fairly accurate. I used this for approximately six months now with no failure.

This AcuRite Digital Wireless Fridge and Freezer Thermometer with Alarm is something no refrigerator should be without. When we one day opened the freezer to find that everything had thawed, we figured our 5 yr old fridge was shot, but after having an LG rep out to inspect it, he indicated that there was a build-up of dust on the coils on the back, which tripped the freezer into shutting down (a safety feature). Simply vacuuming the unit resolved the problem! But this pointed out the need to monitor the temperature in both fridge and freezer, as well as to roll the unit out from the wall yearly and vacuum - more frequently if necessary.

After looking at dozens of in-compartment thermometers we thought how easy they would be to be lost in the mass of food items in each compartment, so we found this AcuRite unit and it is ideal! It easily affixes to the outside of the refrigerator and is easily viewed. More importantly, it is a constant reminder to check!!! We have other AcuRite products, most notably the indoor/outdoor weather stations, and are familiar with AcuRite products over the years. Their products are very well made, stylish, accurate and very functional - and they are durable, meant to last years.

I gave it five stars because that's the highest. I can not say enough about this product. I have a 20 cu ft freezer that is in my garage. First time I lost everything the power went out and my outlet did not turn back on. So I plugged it into a power strip, lights on, great. Until, the thermostat went out, light on, no cold temp. Bam lost more food. A friend told me about this and how good it was. The unit sits on my counter in the kitchen on the ledge about my sink so every time I'm at the sink I can see it. It has gone off once. It beeps like a smoke detector but not as loud, my dogs certainly heard it, it took a minute or two to figure out what they were barking at. My freezer temp had actually gone 1 degree lower than I set it causing it to go off. I use the freezer side for my garage freezer and the refrigerator side for my kitchen refrigerator. Plus it has a reading of the high and lower temps for the last 24 hours. This is worth it's weight in gold. Just think how much money you have in your freezer or refrigerator. This is a bargin.

We have three chest freezers, two of which are out of sight in the basement and full of veggies from the garden, venison from the property and meat from our nephew's farm. The concern has been losing either one, or both if the GFCI trips, and their contents. One freezer is about a year old and the other just a couple months.
I saw this system recommended on a FB group and the Amazon reviews seem favorable. So I decided to give it a try, especially since it has a WiFi connection, so the information display can be in the house, and an alarm. We can check the freezers' status at any time and the alarm will warn if we have a pending disaster.
It arrived well-packaged. The box exterior is plain cardboard with a plain label just at one end. No fancy marketing! I ordered four AA Lithium batteries at the same time for the sender units, which are recommended by the manufacturer for use in freezers. After installing standard 'Copper Top' batteries in the display first, then the lithiums in the sender units, the temperatures of each sender unit appeared on the display immediately. They were the same at about 72F.
To me, the instructions were clear, though it probably does help to be mechanically-inclined! I set the alarms for min and max temps and took the sender units down to the freezers. I hung them on the baskets with tie wraps as the included suction cups wouldn't have stuck on the dimpled freezer walls. The Amazon photo showing the silicone loop wrapped around itself is not very practical as the loop is small compared with the size of the sender unit and you'd have to really stretch it. Too much effort in the depths of a full freezer!
When I returned to the main floor, the alarm was sounding. The displayed temperatures were slowly going down as the sender units adjusted to the freezer internal temperatures, but were higher than my max temperature settings. I pressed the "Bell" button to put the alarm to sleep. The display seems to update every few seconds, not instantaneously.
After a few minutes, the displayed temps reached the freezer internal temperatures, which were just below 0 deg F. Each reading was slightly different due to being in different freezers of different makes and settings and the temps vary anyway within a few degrees as the freezer compressor cycles. 0 deg F is what is expected though for a chest freezer. I have my alarm settings at -20F and 15F for both freezers. The alarm won't go off for a few minutes if it reaches those temps. This avoids alarms when the freezer lid is opened to put in or take out food.
The signal display was indicating max. strength with the display unit maybe 20 ft (straight line) away from the freezers on the floor above. Moving at least double that into the kitchen, where the signal has to pass through a thick natural stone wall in the basement, as well as the floor structure and around various steel/wood heating ducts in the floor, the strength was still high. I was impressed, considering the sender units are also inside a cold, metal box!
The two small magnets on the back upper corners of the display unit, aren't quite strong enough to hold it firmly onto the refrigerator door. It slides down as the door is shut and there's a risk of it falling off and being damaged. I have it sitting on the dining room dresser, where it's out of the way, but visible. It could also be hung on a nail on the wall.
While a little pricey compared with other similar units (with more 1 Star reviews!), $35 is a small price to pay to avoid spoiling all the valuable food that is in the freezers!
So far the system is performing well and to design. I will update should anything go wrong!
UPDATE:
Several months in and the system is working just fine. After the first week or so, I noticed one of my freezers was 10 degrees or more colder than the other and unnecessarily so. I adjusted it and now I have comparable temps, though the later-purchased freezer has a wider range of temperature fluctuation , due to a less precise control system. Very pleased!