"Construction Area - Authorized Personnel Only, Hard Hats Required" Sign By SmartSign | 10" x 14" Aluminum DURABLE ALUMINUM. Signs are made from heavy-duty, 40 mil thick aluminum. Unlike steel signs, our aluminum signs do not rust. Signs last up to 7 years outside. 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. EASY TO INSTALL. Signs have four 3/16" od corner holes. Mount with screws, nails, tie-wraps or wires. Signs can also be attached with foam or double-sided velcro tape. Sign attachment accessories are not included. SAFETY AWARENESS. Alert everyone to exercise caution while taking some burden off your shoulders, regarding safety on your property. Make sure that trespassers stay away and that employees wear their safety equipment.