It does not heat up enough to keep a drink hot in a ceramic cup. You can touch it normally with your hand, for example. Maybe with a metal one like the one shown, although I still don't think so

Very mediocre. It is only nice as a gadget and maybe as a multi-port USB, but it definitely does not keep the coffee warm, practically no difference, and also, it does not come with a metal cup, as the pictures usually show, something that might have worked a little. With ceramic cups, no way.
So it's better to look for something guaranteed good. This is not it.

Don't waste your money if you need a USB hub and a so-called coffee warmer that can't even keep your coffee lukewarm, only if the cup is metallic. Then this is the product you need.

Terrible and useless. I had 6 of them, all broke, melted, and didn't heat anything. Only slightly warmed the bottom of the cup. It should be noted that in order for it to work slightly better, you have to place a cup with a thin and flat bottom so that the entire surface of the cup touches the gadget 100%, and even then it won't do the job

I had one in the past too, the problem is that it doesn't really keep the drink hot, it just keeps it lukewarm! Waste of money

It reaches a certain temperature, which neither increases nor maintains the temperature of the beverage. It's not worth it