One Aluminum Plate, Supporting All-Weather On-Site Safety Whether a warning sign can withstand the site often depends not on the light, but on the body. The LED Arrow Board uses a one-piece bent aluminum alloy plate to build its main structure, solving from the material source the problems of traditional warning signs — easy rusting, easy deformation, and bulky handling — allowing the device to operate stably for long periods in rain, snow, fog, severe cold, and heat.