With the GraviTrax marble run system, you can creatively build your own marble run worlds according to the laws of gravity. Use the building elements to develop an action-packed course where the marbles roll to the finish line with the help of magnetism, kinetics, and gravity. The GraviTrax marble run system can be endlessly expanded with additional building elements, levels, and spectacular action stones for lasting fun. Contents of the starter set: construction plan booklet, task booklet, 4 base plates, 2 transparent levels, 6 marbles, 40 large height stones, 12 small height stones, 21 curves, 3 intersections, 2 switches, 1 3-in-1, 1 vortex, 1 start stone, 1 action stone Gauss cannon, 3 long tracks, 6 medium tracks, 9 short tracks, 1 target ladder, 4 base stones, inserts for the base stones: 2 catchers, 1 free fall, 1 splash, 1 target. Warning: Not suitable for children under 3 years due to small parts that may be swallowed.