EXPAND YOUR MARBLE RUN - This expansion pack (not a stand-alone marble run kit) enhances National Geographic Glow in the Dark Marble Runs (non-magnetic) with 20 additional construction pieces that fit snugly so your marble maze won’t fall apart: 9 tube pieces, 9 action pieces, and 2 base pieces. GLOW IN THE DARK MARBLES – add 5 new glow in the dark glass marbles to your collection and watch them shine bright as they zig-zag down the marble run. UV LIGHT – a UV light comes with the expansion pack to help give your marbles the ultimate glow. GREAT STEM TOY – the learning guide inside teaches about the physics of motion and aerodynamics. It also includes marble run construction experiments HIGH-QUALITY EDUCATIONAL TOYS - We're proud to make the highest quality hands-on science toys, and all our products are backed by exceptional service.