If you go to buy a cage, you will find that the quality of the cage is mostly iron, with wire, or columnar square iron rod. For smaller dogs, wire is available, but for larger dogs, it is necessary to choose square iron rod, which is stronger than wire. Not a few. The advantage of wire is that if you don't use it, it can be folded and folded up, but the iron rod can't. There is still a small cage of pink square iron rod used in my family when I was a child. Although it's useless, it's thrown away and wasted, so I left it at home.