The middle pull rod with the same width as the box body not only has the center of gravity more stable and easy to push, but can be completely hidden on both sides of the box body after being retracted, does not occupy the space in the box, and has a more concise and powerful appearance. There are four colors and three contrasting colors. The colorful colors are popular with young people. Polycarbonate material, using injection molding process, so that the box is not easy to fade, stronger. The balanced series was released in 2019 and won the Good Design Award in Japan after it was launched.