Review on NG1702 - Mustard USB Cup Mug Warmer Coaster in Dark Brown Hot Cookie by Fuzzhead Nelson

I should have read the reviews before buying. Although warm to the touch, it doesn't generate enough heat to heat up the mug and keep it warm. I even tried using a flat bottomed water glass and it barely kept the temperature above room temperature even when there was almost no liquid in the cup. The packaging says it works best with metal and flat bottom cups (I've tried flat bottom cups to no avail) but the print is small and shows a cup on the packaging so this can be misleading. It's very pretty, but I doubt I can even use it as a candle warmer.