These 10 sturdy Alphabet Stacking Cardboard Blocks are lightweight yet strong! Made of a strong, heavy-grade cardboard, each brightly-colored block can be stacked 3 feeet high to make endless building combinations such as letter, color or size! These blocks stack as high and wide as a child's imagination. The Alphabet Nesting and Stacking Blocks are fun blocks to practice the ABC's with colorful and fun animals! Biggest block is 5-3/4" square. Suggested Ages 2 years+