You show a ball which freely slides down on, a thread. Whenever you so wishes, the ball stops sliding and freezes in place. A spectator may be invited to shout "stop" as the ball is sliding down the string, and the ball will stop where required.
In this new improved version of the trick, the apparatus may be handed over to a spectator for examination, and there will be no way for them to make the ball stop, or detect the secret of the effect. Made with a large ball 2" in diameter, this can be carried in your pocket, yet performed for a large audience on platform or stage. Supplied complete with instruction.