Get specific when shipping Dangerous Goods with Labelmaster's Personalized Dangerous When Wet Imprinted Placards. Imprinted with your UN Number, these Hazard Class 4 placards meet the requirements of 49 CFR 172.500 for domestic and international shipments of hazardous materials by highway, rail and water. Your compliance is our top priority. From proper ink coloring and pictographs to exact wording and sizes, we cover all the bases so you can rest easy with 100% confidence in your placard solution.