The interactive marble run system from Ravensburger. With the GraviTrax marble run system, you can build your own marble run world by creatively using the laws of gravity. Use the various building elements to create an action-packed course and guide the marbles to the finish line using magnetism, kinetics, and gravity. With the GraviTrax marble run system, you can playfully discover gravity, and with various expansions, it can be enlarged for limitless building and playing fun! Add even more speed with the expansion sets. Reach new heights! With the GraviTrax PRO Vertical Expansion Set, you can easily place elements of your track where you want them, saving height stones. Build tracks at different heights above and below each other, and go through pillars instead of building around them! Build smartly and let the marble roll through tunnels along the way. Combine the expansion set with your GraviTrax Starter Set and create exciting new tracks. How high and cleverly can you build with the Vertical expansion? 33-piece set. Only to be used in combination with a GraviTrax® Starter Set. Contents: 12 pillars (8 solid, 4 tunnels), 2 long transparent walls, 3 medium transparent walls, 16 classic balconies, manual (D, F, EN, NL, E). Age 8+