Each set is made up of hollow stacking cubes and a variety of perfectly flat tracks. The paths cut out of each track widen almost imperceptibly from one end to the other, creating an invisible slope that propels the marbles forward.
Builder set includes: 1 catcher, 1 topper, 55 risers, 5 stainless steel marbles, 10 unique tracks, base grid, instruction booklet to make many exciting ball runs!
