This is a very deceptive and effective penetration of solid through solid. The performer displays a small wooden box with holes on top and bottom and a solid steel ball that just passes through the holes in the box. A glass sheet is placed inside the box so that it obstructs the holes, filling up the entire inside of the box. There seems to be no way now for the ball to go through the holes unless it goes right through the solid glass sheet. Yet the performer does just that--passing the solid ball right through the piece of glass. We supply you the special mechanical box approximately 1.5" height and 2.5" x 2.5" length and breadth, made from beautifully polished teak, a solid steel ball of the appropriate size, and the "glass" sheet, (actually clear acrylic), with full instructions.