Discover marble mayhem inspired by our Toy of the Year Award-winning Tumble Trax® with this introductory marble run set. Using the set's cling-back pieces, build tracks on walls and windows to solve STEM challenges! Self-adhesive cling-back pieces require no permanent adhesive! Includes 13 track pieces, 2 balls, and double-sided challenge cards.Dimensions: 10 x 9 x 4.5 inches