Fat Brain Toys Dado Cubes Set of 10 graduated cubes scaled from 1 inch to 5 inches; slits on each cube interlock with the other cubes to create unique, creative structures; features bright, vibrant colors Stack and arrange the cubes any way you want; arrange them by size and nest them together; push yourself to explore and invent new ways to build Fun for anyone ages 3+; meets or exceeds all safety standards and regulations; durable, heavy-gauge plastic construction; BPA-free Strengthens visual-spatial skills, creativity, spatial awareness, fine motor skills, planning, critical thinking; inspires children to think imaginatively, communicate their ideas, express themselves Winner of 12 awards including 2006 National Parenting Center Seal of Approval, iParenting Media Award, 2007 Dr. Toy Best Products Winner, Creative Toy Awards 2007 Top Toy of the Year Award, and more; developed, manufactured, assembled in the U.S.A. Strengthens visual-spatial skills Encourages creative exploration Inspires the imagination Improves fine motor skills Inspires innovation Proportion, balance, structure, color Endless ways to build Graduated cubes nest for storage Frustration-free packaging