Automatic sleep mode.
The lighted Evoluent logo on the vertical mouse is not just a nice eye catcher. It is also an indicator, if the Evoluent4 Right Wired Small is in the sleep mode or not. The illumination turns off when the system is in sleep mode to conserve laptop battery power. A well-thought-out function, which can be very helpful, when you need to save the battery power of your laptop.