For boys
Target age: From 15 years old, parts with sponge sheets pasted are attached to the underside of the car body. When changing lanes or on slopes, the sponge contacts the road surface and applies the brakes to the machine, preventing it from going off course. There are two heights to choose from, one for small-diameter tires and one for large-diameter tires, and a set of two types of sponges with different hardness. The brake surface consists of four parts that can be replaced and two types of hexagonal shafts, allowing for various settings. (From Discovery Japan Mall)