Build new routes and create crazy trick shots, expand the marble run with new ideas, expansion sets to keep the ball rolling compatible with all GraviTrax & GraviTrax PRO sets & accessories\nExperiment with gravity to power your ball through twists, loops and turns in a race to the finish line great building game for boys & girls\nA GraviTrax Starter Set is required to use expansion packs & accessories. No batteries required. Other accessories sold separately.\nSTEM and construction toys for kids age 8 years up. Great Christmas gifts and birthday presents for children.