"Beware Of Dog - Do Not Put Fingers Thru Fence, Dogs May Bite" Sign By SmartSign | 12" x 18" 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 63 mils thick aluminum and last up to 7 years outside. Signs do not have a low-cost plastic core. LAMINATED. Graphics are protected from weather and abuse. Graffiti can be cleaned off. Laminated signs outlast competitive unlaminated or overcoated signs. 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. GIVE A HEADS UP. Convey your Beware of Dog warning with this sign - before you have to intercede personally. 100% rustproof aluminum Laminated for superior outdoor durability, chemical, abrasion and UV-resistance Signs can be mounted with screws or nails 10+ years of outdoor life 23&#034; Fence Bracket Attachment Hardware Kit for 24&#034; signs 17&#034; Fence Bracket Attachment Hardware Kit for 18&#034; signs Chain-link Fence Clips for signs 5&#034; to 72&#034; wide