From the Manufacturer
Compost is all about accurate temperature. This 20-inch thermometer measures up to 220 degrees Fahrenheit - perfect for measuring the temperature of the heat core of your compost.
Customer Rating: 
Summary: Really handle with care
Comment: This thermometer worked well for a while then got stuck at 80 deg. I think the shaft twisted slightly apart from the face part as I pulled it out of one of my compost piles.
Customer Rating: Summary: Regardless of negative reviews - I bought and it failed miserably
Comment: I figured I would give this item a try even though there were quite a few negative reviews. The item was shipped and received the day after I had bought it here at amazon (new - not used). I was caught off-guard when the thermometer was shipped in a piece of folded cardboard and not in a box. Upon opening the package the thermometer did have its own box, but whomever shipped it decided to crush it in a cardboard sandwich which might have worked quite well except the thermometer stem which has the same strength as the am/fm antenna on your car had a nice big bend in it. However, even this didn't deter me as I figured the technology in thermometers is proven and the bend wasn't a crease - so I straightened out the stem and stuck it in my composter. My pile had been going for four days and was nitrogen rich, so when I stuck the thermometer in and it read 75 degrees F I knew it wasn't working (It was July in Dallas and our daily temperatures average 3 digits alone - nevermind the heat generated by decomposition). To confirm this though I did stick a digital thermometer into the middle of the pile and it instantly read 105 degrees F. Thermometer might have worked if it wasn't packaged improperly; however, I still would be unsatisfied with the overall quality and durability of this item in correlation with its price tag. Mine is being returned and I think I'm just going to use a simple and cheap digital meat thermometer for my compost since it seems to work so well and gives an instant reading.
Customer Rating: Summary: It measures temperature.
Comment: This thermometer measures temperature, which is to say that it displays a reading of the thermal activity contained within the object into which one inserts it. It's flimsy, sure, but it's also long.
I give it four stars only because it would have been nice if it were powder coated in rainbow colors.
Customer Rating: Summary: handle with care
Comment: Mantis Compost Thermometer #201101These are tricky to handle; if you so much as twist the dial getting the thermometer out of the package it won't work very well, if at all. Instead, hold the thermometer by the probe. I use 2 of these in the barn to measure the temps on my hay bales and when handled correctly, they give very accurate temperature readings.
Customer Rating: Summary: Cheaply made
Comment: I ordered this from amazon as I do purchase frequently and usually have good results. Not so with this item. It was used once, maybe twice, when it stopped working: the needle wouldn't move off of 140F. With some experimenting, I found that when the probe was twisted, the needle would move proportionately. Somehow I don't think that's supposed to work in that fashion.
There are other compost thermometers out there; I think amazon may want to consider carrying the REOTemp brand insted of this.
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