STEM Explorers™ Marble Runners, Discover marble mayhem inspired by 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! No permanent adhesive required! Includes 13 track pieces, 2 balls, and double-sided challenge cards. Recommended for ages 5-10
