very good user reviews.
take your pick of the retailers.
* 15 months of battery life
* Laser tracking delivers smooth, responsive, precise cursor control on surfaces that cause problems for optical mice
* Tiny Logitech® Unifying receiver stays in your notebook. so there's no need to unplug it when you move around
* Ergonomically designed shape with soft rubber grip conforms to your hand to be naturally comfortable
* Logitech® Advanced 2.4 GHz wireless connectivity gives you the reliability of a cord plus cordless convenience and freedom fast data transmission and virtually no delays or dropouts