Is the suitcase zipped or aluminum framed?

Zipper box and aluminum frame box are not absolutely dominant.

Early suitcases were made of wood or other heavy materials. With the popularity of air travel, the material of luggage tends to be lighter hard plastic or cloth. Most models are also equipped with built-in wheels, which can be easily pulled by a pull rod. After 20 10 years, there are also four-wheeled suitcases, which can not only rotate 360 degrees, but also be easily pushed on the flat ground.