Only with a "lid" on the cup does it keep the coffee truly hot
I was satisfied w/ what it does, but really would like a warmer that keeps the coffee hotter.
But warm coffee is a whole lot better than cold coffee and I really did not expect anything better than what I got.
I use a slightly oversize mug that does fit, which I was a bit concerned about.
update
There is a simple way to keep the coffee warmer - - - put a lid on the cup.
Anything will work, even the cardboard backing of a note pad, but a small ceramic dish works best. With that covering the cup, the coffee not only stays hot, but may slightly increase in temp.
If it does in fact continue working for more than a year, I'll upgrade this to a 5.
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