"My son is 2.5 and LOVES these blocks. Light enough for him to stack as high as he can, light enough to not hurt when they inevitably come tumbling down. Decently durable (he does stand on them), but still crushable. All in all, a good purchase for the price, they are what they are - heavy-duty cardboard blocks that are folded. Ships flat, you have to build them yourself, but its not hard, especially after completing the first block or so."