This super cute mug warmer is fantastic! Heats up more than I expected, and does as it claims. I accidentally forgot to unplug it one evening and left it on overnight, and when I came back in the morning, my cup of tea was still warm (5pm to 8am)! It's such a simple little change but allows me to get up to refill my tea a lot less often. Super handy (did I mention cute-) and as a huge booklover, speaks to my soul. Love it!