Inspection of travel bags (old version)

Early suitcases were made of wood or other heavy materials, and with the popularity of air travel, the materials used in suitcases tended to be lighter, hard plastic or cloth. Most models also come with built-in small wheels, which can be easily pulled by a lever. After 2010, there were also suitcases with four small wheels, which can rotate 360 degrees and be easily pushed on flat ground without any effort. In addition, luggage can also be divided into hard shell luggage and soft shell luggage according to the outer shell. Hard shell luggage is more resistant to falling and is suitable for luggage that requires more protection. Soft shell suitcases are usually lighter in weight than hard shell suitcases and have more elastic capacity. However, the zipper position of a soft shell suitcase is more likely to explode due to too many objects inside. The size of luggage on the market is generally based on the size regulations of the carrier (hand luggage) and check-in box (cabin luggage) of the airline (International Air Transport Association). For example, Cathay Pacific stipulates that the maximum size of each piece of cabin luggage must be less than 158 centimeters, while the maximum size of each piece of hand luggage must be less than 56x36x23 centimeters