Shaan received two Erector Construction kits for the holidays. We had fun building a bi-plane. I played with Erector sets when I was a kid and had hours of fun learning. Shaan's kits are plastic pieces for the 4-8 year old. The sets I played with as a kid were metal. Erector sells those for the 8-15 age range. Two more years and my young engineer and I will be tearing the house apart and blowing things up in the basement lab.