The ARCTIC M551 comes with a short user manual that explains its buttons and the three DPI settings.

Download the User Manual: Link

As like many other gaming mice, the ARCTIC M551 features adjustable sensitivity via the DPI switch button. The three sensitivity settings are 800 DPI, 1600 DPI and 2400 DPI. Each setting is associated to a different coloured LED. The LED is quite bright, but it shines indirectly towards the user. Furthermore, your palm will most likely cover the LED, so it will never blind you.


The different DPI lights of the ARCTIC M551: green (800 DPI), blue (1600 DPI) and red (2400 DPI)

In terms of drivers, they are automatically installed by Windows 7 Ultimate. There is no software provided for the ARCTIC M551. Customization of the thumb buttons are not easily done, as such.