Expand yout possibilities! The Building Expansion offers over 25 additional elements to expand your track vertically. You'll increase the action when increasing the height of your run. Experiment with the combination of height tiles, base plates, freefalls, switches and even another level. See how high you can build your track before getting the marbles to the finish. GraviTrax Starter-Set required Contents: 2 Base Plates, 1 Transparent Level, 8 Large Height Tiles, 4 Small Height Tiles, 2 Switches, 1 3-in-1 tile, 1 Vortex, 1 Finish Line, 4 Basic Tiles, inserts for basic tiles: 2 Catchers, 1 Freefall, 1 Splash, 1 Landing