How to choose and buy the cases?

At present, the development of the aluminum trolley case is faster and faster, a variety of trolley cases to be designed, they are used everywhere. You will prefer to take a case when have a travel. How to choose and buy the cases? First, make sure the aluminum travel case with rotary wheels, and can be pushed when it stand up to flat. The case like this will easy to carry. Second, pay attention the tie rod, the material will be aluminum alloy, it will stronger than others.