"Yield" MUTCD Sign By SmartSign | 18" Triangle 3M Engineer Grade Reflective Aluminum 3M AUTHORIZED. Authorized signs are certified to the 3M Matched Component System. This assures that signs are durable outside. DURABLE ALUMINUM. Signs use 3M reflective Engineer Grade film mounted to 80 mils thick aluminum and last up to 7 years outside. Signs do not have a low-cost plastic core. ROUNDED CORNERS. Signs have rounded corners and burr-free corners for safe handling, longer life and a professional appearance. INSTALLATION. All signs come with burr-free corners and 3/8" punched and pre-cleared holes. Signs mount to U-channel posts, square or round galvanized posts, wooden posts and chain link fences. ORIGINAL DESIGN. After countless and actual field testing of durability, plus years of customer feedback, we have confidence that our Yield signs out-perform and outlast others. With so many counterfeits of uncertain quality, it is easy to get overwhelmed with too many choices. Buy the original. GOVERNMENT APPROVED. Signs are MUTCD compliant and professional.