Young construction workers and architects will spend hours with these lightweight yet durable cardboard building blocks. This 40-piece set features three sizes of "bricks" for constructive imaginative play. Made of premium, extra-thick cardboard for strength, they are easy to assemble and feature a wipe-clean surface. The red blocks hold up to 150 pounds! Details • Includes 40 blocks in 3 different sizes • Made of premium, extra-thick cardboard - red blocks hold up to 150 pounds! • Bright, colorful graphics on every block • Includes step-by-step instructions for easy fold-together assembly • Lightweight and easy for children to lift