Originally Posted by Concerned Continental Pilot

Can't speak for any other airlines but at CAL the following applies. I guess the colors are blue and red so the F/A's can look and see if the power to the plug outlets has been turned on/off, or to remind the pilots to turn on or off the sterile cockpit light.

We turn the sterile cockpit light on during our after start check list and turn it off climbing through 10,000 ft MSL and back on descending on through 10,000 ft MSL.