Product review (4 stars): Be careful installing it
I didn't look closely, and the heat rod is NOT a Calrod - it's a glass tube.  So, after I broke it and paid over $50 for a new one to be quick-shipped in (it's not available on Amazon), I carefully enlarged the curved end of this Heat Probe and shaped it to accurately fit over the NEW glass heating rod, and then installed it.  The screw included with the probe wasn't large enough to allow the probe to fit onto the heating rod in our freezer, but a longer screw VERY LIGHTLY tightened and with some Loctite added has held it in place so far.

Also - the included metal insert for the drain tube in the refrigerator or freezer was far too large to fit into ours, and despite the instructions saying to pull out the existing drain tube - it's part of the plastic liner in our model.  Fearing the drain area might overheat, I looked through the house and garage for a suitable piece of thin copper, brass, or aluminum tube to ensure that if the probe touched it, the heat would be spread out and no plastic would melt.  Bingo - a .30-'06 casing is the perfect diameter, though it took a while to shape the bottom end nicely to permit it to be inserted, and flare the top enough to ensure a good seal.  Once completed, I had a custom brass insert.

Now that the probe is in place, it seems to work well.  Sadly, we'd already replaced this freezer before I found this part t solve the prior freeze-up frustrations that had made one too many puddles, so I only repaired the old freezer to either sell or move to the garage.