4" x 4" class 8 DOT hazard labels signify corrosive materials. For packages with class 8 DOT labels, proper precautions must be taken to maintain the safety of the individual handling this package as well as any adjacent materials. With class 8 DOT hazard warning labels from The Label Supplies Shop though, anyone shipping or handling a package with these labels will know to take extra care because corrosive materials are present. For more savings, purchase 5 rolls or more!