Kids will spend hours building life-size castles and fortresses with these study blocks. Constructed of lightweight corrugated cardboard, if the blocks tumble, no one gets hurt! In addition to our award-winning basic blocks, these sets contain arch pieces, castle door/drawbridge pieces and turrets. The blocks are printed with non-toxic inks and with their water-resistant coating are strong and durable for years of creative play. Ages 18 mos.