Sometimes sound mixing in specialized environments require that you work in the dark. Even a small console light is more than the event manager will allow for certain dramatic parts of a show.
When this happens, small pieces of glow tape fixed to critical controls on the console can help you grab the right knob in the dark.
Just a sliver of glow-in-the-dark tape affixed to a critical fader handle or mute switch will make sure that you hit the mark, even when the mix position is in black out mode.
It has an adhesive that is safe for expensive electronics and can be re-positioned to another point on the mixer for later use.