You'll be amazed as you watch glowing marbles race down the 50-piece National Geographic Glow-in-the-Dark Marble Run! 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! Details: Multicolor 41 construction pieces and 8 glow-in-the-dark marbles Use included UV light keychain to charge glow-in-the-dark marblesIncludes CR2032 lithium batteryIncludes storage bagCompatible with other National Geographic Marble Run setsFor ages 8 and up