Although I, for the most part, like this product. It can be improved upon. 
Suggestions: 
1) Battery powered...with today's technology, I'm sure the heat needed can be produced by a cell battery, rather than being restricted by a cord and outlet. Like the pictures give the impression of...
2) No on/off switch just have it start heating upon a ceramic touch to the pad heating surface. Goes off with 30 seconds when pad not feeling any weight or utilized. This will prevent it being left on accidentally causing unwanted damage.
3) The pad surface needs to increase its diameter by about an inch. The manufacturing of enormous coffee cups are prevalent in today's society and this mug warmer should accommodate these mugs as well.
4) Little 1/2" plastic molded ridges need to surround the pad surface as to prevent knocking coffee mug over and spilling next to work computer, as to give it a cradle effect.