Not really, honestly, free roulette, this is what we have done best so far in terms of comfort: none. This mouse is great: an incredible design, comfortable grip (materials, shape, extremely wide skids), the battery life is very good, the SetPoint driver is (for a time Logitech has made an effort !!) and now, in terms of price, it becomes affordable. In two words: GREAT PRODUCT.
EDIT: There is an error in the description. This mouse is powered by one AA battery, not 2 as shown.