roissyJust came here to say the same thing. The surface area on top of these is way too big to retain heat well, completely defeats the purpose of the insulation.
roissyHa--this is how ugly rumors are started!
I have a similar, large-size mug (don't know the oz's) but it is definitely wide, and has no problem keeping its contents HOT.
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Plenty of similar styles and sizes on Amazon, of course, and no need to purchase EIGHT unless you really need that many.