The National Geographic Glow-in-the-Dark Marble Run is a phenomenal construction activity kit for kids! This 250-piece set has everything you need to create incredible marble runs that will have your glowing marbles racing toward the finish line! Inside this kit: 50 Glow-in-the-Dark Marbles A UV Keychain Light to Help your Marbles Glow Brighter, Longer 130 clear, smooth-run tube pieces that fit securely together 58 action pieces that fit securely together A full-colour detailed learning guide All of the pieces in your marble run kit fit securely together so you can be sure that your marble run maze won't fall apart when you play. Configure the pieces in any design you'd like - the possibilities are endless! A detailed learning guide has lots of information about the physics of motion and gravity, so you can learn while you play! And when you're all done, a convenient mesh storage bag is included so you can keep all your marble run pieces stored together. National Geographic Toys is hands-on-science toys providing only the highest quality products and exceptional service. About the National Geographic Society: With a mission to inspire people to care about the planet, the National Geographic Society is one of the world's largest nonprofit scientific and educational organizations.