Unique thumb wheel: for horizontal navigation and advanced gestures Easy connections for multiple computers: use with up to three Windows or Mac computers via included Unifying receiver or Bluetooth smart wireless technology Easy switching between computers with the touch of the button Advanced power management: up to 40 days of power on single charge. You can get enough power for a full day of usage in only 4 minutes, with No downtime while recharging Tracks virtually anywhere even on glass: the dark field sensor tracks flawlessly even on glass and high gloss surfaces (4 millimeter minimum thickness)