Music Motion adds a musical element to the marble run formula! Music Motion includes xylophone keys that are placed into different building pieces, so marble run builders can get even more creative with their construction! Set them up in crazy ways, or why not try having marbles play a tune as they roll down the raceways? Music Motion can be combined seamlessly with other Quadrilla marble run sets. Music Motion Marble Run set is crafted with high quality birch and rubber woods and metal xylophone keys for long-lasting musical marble fun! For ages four years and up.