With the gravitrax interactive track system and marble run, you can design and build your own race tracks and experiment with gravity, magnetism, and kinetics to propel your ball to the finish. With a variety of tiles, levels, tracks and features, you can control the speed of each ball. The open-ended building concept offers endless possibilities to design a different track every time you play. Add flair and speed to your tracks with expansion sets and action accessories. Gravitrax is a fun STEM toy for boys and girls that comes with over 200 pieces and 3 action accessories already included. The GraviTrax Starter Set XXL offers everything you need to begin building your own action-packed track systems.