When you think of telling time in the dark, you’re thinking of one of a few things – lume (whether paint or tritium), backlighting, or flipping on an electric light (or flashlight).  However, not too long ago, those weren’t really options.

This article (link) over on Watchpro is really focused on the recent resurgence in the high-end minute repeaters available today.  However, it does give a quick overview on how the wristwatch version started in clocks, and eventually miniaturized to what we have now.

And lest you think that this is some “simple” mechanical alarm, definitely read the article (or this one over on Wikipedia) for how exactly these particular marvels function.

And, if you’d like to see/hear one in action, check out this video: