Alert others to a hazardous work zone with the Brady 10 in. x 14 in. Plastic Caution Hard Hats Required OSHA Safety Sign. The bold black font over bright yellow background is designed for better visibility. 1-sided Black font over yellow background for visibility UV-resistant plastic and protected graphics for durability Suitable for indoor and outdoor use 1-2 year outdoor life Great for light-duty industrial, utility, commercial and institutional environments Rounded corners with 4 holes for easy mounting