Watch your marbles take off like a shot with the “GraviTrax Magnetic Cannon”!Launch the marble through your run by adding the Cannon. The high-powered magnet gives the marble speed to help extend your run by boosting it up inclines and down tracks. This accessory also includes 3 additional marbles.GraviTrax Starter-Set requiredWhat makes a great toy? GraviTrax checks all the boxes! It’s a creative, modular, expandable track system that challenges children to use their imagination to design and build their own marble runs! Electronic-free, GraviTrax construction sets use STEM-friendly concepts while building critical thinking and problem-solving skills. Completely open-ended, every GraviTrax set has a boredom-busting variety of play options for hours of fascinating fun. Once the basics are mastered, simply add expansion sets and accessories to propel those metal marbles around the tricked-out track of your dreams!Comes complete with 1 Magnetic Cannon, 3 colored marbles and instructions.