The interior light billboard is commonly known as the outdoor light box. The materials of the spray painting are different, and the built-in light tube, so that the picture of the billboard during the day and night is very clear. Good light transmittance, uniform, relatively high brightness.

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.