A:Answer To answer your second question. All mice use a an electric light to track surfaces, but standard mice use an LED for it, while laser mice use an actual laser for it. Laser is generally more accurate and usable on more surfaces.
The M510 "appears" to come in both varieties. I have two of them and one clearly has a laser module and is marked as such. However, a different M510 that I have is NOT marked as having laser capability and has a different style lens assembly.
More confusing, the package for the second one says that it has "laser grade" capability, not that it is actually a laser mouse.