Just got this set for my four year old son today. He is absolutely enthralled and won't stop playing with it. And he is a kid that usually gets bored with things relatively quickly. The "lab" has a little black light gun that "paints" designs on the cars that then slowly fade away. It has stencils and a "robot arm" for lining up the car and the light. He loves it! I love it - no mess, super easy to use. Needs no batteries. It was easy to assemble and all the small pieces have little places to stow them on the kit. Such a clever idea! For the price, it might just be the best toy ever.