The Cherry MX Board 6.0 features full LED backlighting, which have many levels of brightness. This is the first fully backlit keyboard that I have seen from Cherry. The LEDs on maximum brightness are incredibly bright. This particular model has red LEDs, with some blue.
Some keys have dual colour LEDs if they can be toggled. Below you can see that the windows key and Caps lock are blue. This is the case when they are currently active. When they are disabled, they have a red LED.
The brightness can be controlled by the F5-F8 keys. The brightness is based on a scale of 0-100 With 0 being off. The F5 and F6 keys go up and own in increments of 1, whilst the F7-F8 keys go up/down in increments of 10. I’m not sure as to why the keyboard needs this level of brightness precision, but still, it’s pretty cool to have this level of control.