I think this is probably what you are looking for:

http://www.cpfmarketplace.com/mp/showthread.php?s=99a9f80ccaf3e2c9762386b9436446f3&t=169314

He's not here in the states, and you can't really find a supplier in the U.S. because the NRC deems them to be used for a "frivolous purpose". It's o.k. if it's on your handgun sights or your watch, but not your keychain. Go figure!

There are also just the little vials without the plastic keychain if you look around on the B/S/T forum of candlepowerforums.com. You have to protect the vials from breaking because they're glass. Some people mill small slots into something and put them in with a bit of clear epoxy. I've got a few and think they're pretty neat. Great to have on your flashlight, because then you can find your flashlight in the dark.