Dell Alienware 15 (Early 2015) - Manual (Page 18)

Keyboard
Shortcut Keys
Allows to disconnect Alienware Graphics
Amplifier
Disable/Enable wireless
Mute audio
Decrease volume
Increase volume
Switch to external display
Decrease brightness
Increase brightness
Disable/Enable touch pad
Disable/Enable AlienFX
Macro keys
NOTE: You can configure modes and assign
multiple tasks for the macro keys on the keyboard.