The ideal auxiliary appliance for small kids learning how to maintain balance while avoiding risks of injury. The bike is ultra-light, weighs only 3.3 kg and is made of alloy materials. The production process also breaks through the traditional manufacturing methods such as cutting and welding. The head tube has a ball-shape design and is connected to the one-piece frame. On the rear end of the frame, the wheel rim is reinforced by two pieces. It is not welded and has a simple and clean shape. The wheel rims keep the smoothly curved surfaces on both sides, reflecting dynamics, and maintain the metal processing aesthetic feeling.