Great little mouse! Excellent tracking, zero lag, works on any surface but glass, comfortable to use, and very durable. I've dropped this countless times (seriously, about 3x week lol) and all that happens is the cover comes off and the battery falls out. Snap it back together and it works like it did from day one. I love it so much that I'm getting one for my desktop at work (graphic design). It's not often that such an inexpensive product works as claimed. This exceeds them.