I thought I would try this product instead of Technic. BIG MISTAKE. The very first part of the manual talks about missing parts. THE VERY FIRST THING. Guess what? There were missing parts. NEVER MISSING WITH TECHNIC (I have built about 15). It was one of the most frustrating things I have ever done. I excitedly bought 2 different models. Halfway through the first one I gave up. They just sit in the boxes now. I am too embarrassed to even give them away. I KNOW, LET'S STRIVE FOR ALL OF THE PIECES BEING THERE 100% OF THE TIME. If you are used to Technic models, DO NOT BY THESE. YOU WILL BE DISAPPOINTED.