Basically, because the laser is a uniform tight beam, it reflects more detail from minor surface defects and textures, even on what normal LED illumination shows as uniform-color smooth shiny surfaces (like white board), resulting in, "20x times the tracking power of optical." (That is, it can navigate on surfaces with 20x smaller surface features.) Logitech still warns that the "Laser still may not track on mirrored or clear surfaces, such as windowpane glass."