Anybody seen this trick, what's inside the Bolt?..

 

Yes I have 2 or 3 of them, it works on Faraday's motor principle.
There is a battery in side the bolt head and a small thin magnet taped to the ball of the thumb.
There is a also the same trick with a drywall screw and battery.
Max.

 

Michael Faraday's Homopolar Motor. (another version).

Max.