*EDIT New movie file:
My brother designed and built these and I think they turned out very nice. They're no bigger than a credit card and are extremely bright - even in daylight. I used dark green faceshield plastic for the window in my chest armor and it shines a bright red even through the dark window (as seen in the photos and movie clip below). Powered by one 9-volt battery with a cord that measures 22" long for easy storage wherever you want. Be sure to watch the movie clip!
He's selling them for $79 shipped. PM me for more details.