A solid ball bearing, and a brass tube. You can hand them out for examination, either before you do the trick, or afterwards. The spectator will find that the ball will not pass through the tube - the tube is simply too narrow.
However in your hands, the ball will sink into the tube, seemingly by itself. You can blow on the ball, to help it on its way! With a little sleight of hand, you can appear to feed a number of balls into the tube, and then to retrieve them back from the tube.
When the trick is over, you can hand everything out for examination.
This is a magic trick, and in terms of the skills needed, we rate it as EASY.Watch the video...