• 【GraviTrax Series】GraviTrax is a system toy that allows anyone to easily create their own action-packed original courses by utilizing the principles of gravity, magnetism, and momentum The tunnel set is an expansion set that adds new actions to your layout, including tunnel parts that can create blind courses, trucks that can pass through steep differences in elevation, and trucks that drop balls directly below intersections • Build a course with your own original design: By combining various parts, you can design freely, so you can create different courses every time you play Includes a total of 26 pieces, which can be combined with the separately sold starter set for play • 【Enjoyably experience the field of STEM】Through play, you can experience and learn the fields of STEM education (Science = Science, Technology = Technology, Engineering = Engineering, Mathematics = Mathematics) • 【Set Contents】Instruction manual, Base plate x 2, Curve tunnel x 4, Straight tunnel x 2, Switch tunnel x 2, Vertical U-turn tunnel x 2, Basic tile x 6, Tile for straight tunnel x 2, Curved track x 2, O-shaped track x 2, Catcher x 2 • 【What is GraviTrax?】It is a track system that allows you to assemble a course with your own original design and run the ball You can create a variety of courses with your creativity and enjoy your own course with expansion sets and additional parts