There are many kinds. I don’t know what kind of outdoor advertising you are talking about. Outdoor advertising signs generally use zinc iron plates, aluminum-plastic plates, or wooden boards as the base. In some cases, after an iron frame is welded, large-scale features can be made directly on it, such as drawings and text. ah.
When making outdoor billboards, the main thing is to be solid, safety is the most important, and then there are the appearance considerations!