Bardics have been around a very long time. There are two aspect (white, red, green) and three aspect (yellow, red, green, white) versions.
They're not just used as lamps though - they are brilliant as doorstops, passenger subduers, hammers, paperweights etc etc...
They used to be (are they still now?) colour coded. IIRC grey was for railways, green for the army and yellow for oil depots - not sure on that though!!
As said above, the modern equivalent is the Halo lamp, which does the same thing but with high intensity colour calibrated LEDs and a halogen bulb. They can do all sorts of fancy things like reverting to red automatically should you let go of a proceed aspect button - unlike Bardics where you would be fiddling around for half an hour!
