"I wanted to find a set that I could use to introduce my 5 yr old girls to gears. This for the bill just right for them. I had them each choose a model to build in turn. The models in the instructions are easy and entertaining for them; they were very excited about each one. It would've been nice if there were extra gears beyond those used for the models in the instructions, to encourage creativity rather than just following the instructions here, but I suppose I could just get another set for that."