1. There is a hot dip galvanized square tube. The smaller and thinner the size, the more expensive it will be.

2, there is another kind of hot dip galvanized steel pipe, its output is higher, the price is slightly lower, but after using 2~3 years, it is easy to rust.

3, there is another kind of cold galvanized steel pipe, the price is the lowest, about 1 year will appear rust problem.