You’ll be amazed as you watch glowing marbles race down the 50-piece National Geographic Glow-in-the-Dark Marble Run! • 41 construction pieces that fit snugly together • 8 glow-in-the-dark marbles • Use the included UV light keychain to charge your glow-in-the-dark marbles, then turn off the lights and watch them race to the finish line! • Comes with a storage bag for all your pieces • Compatible with all other National Geographic Marble Run sets This set comes with 41 construction pieces that fit snugly together, 8 glow-in-the-dark marbles, a storage bag for all your pieces, and a UV light keychain so your marbles shine bright as they zig-zag down the marble run. A full-color learning guide inside teaches about the physics of motion and gravity. There are countless configurations kids can build with this set, meaning play will last for hours and hours!