The main structure of the external light billboard is iron frame plus spray painting, and some are covered with metal edges, plus spotlights. For example, the production of large billboards, such as billboards on the roof and column advertisements, is the heart of the billboards. It is unsafe to have a solid steel structure as support.

The billboard is a signal tool in the pull system to start the next production process, or to carry the WIP to the downstream process. This term means "signal" or "signal board" in Japanese.

Refers to all outdoor media that transmit advertising information. The media size depends on the actual environment.