I had a "code ring"; it had a rectangular tin box on top, with a worthless little telescope built in. You pressed the top of the box down, and a spot of glow-in-the dark paint showed through a hole in the end, so you could flash code messages, which you could probably see about as far as you could have whispered to some other kid anyhow. What I can't remember, is which of those shows I ordered it from.