These penguins are made out of nice plastic (quite strong and don't look cheap). They are easier to take apart than some of the wooden ones, which can swell and stick together (and are difficult for a child to open). The kid I bought them for loves them. As she plays with it, she thinks and learns clearly to fit the smaller sizes into the larger ones. It's simple, but seems quite enlightening to her. The smallest penguin is likely to be a hazard to a toddler, so I would recommend removing it before giving it to a very young child.