Through the design of the model mechanism, you can assemble a handsome engine car by yourself, and learn the concept of the operating mechanism of the real engine operation mode (V-shaped and horizontally opposed). You can also learn about green energy power: the oxidation-reduction reaction of salt water fuel cells (non-toxic) No batteries are needed, just a drop of salt water, the car can go over mountains and mountains! Twice the learning fun is a must-see choice for children who love cars!