"In Case of Fire - Use Stairway for Exit, Do Not Use Elevator" Label by SmartSign | 8" x 5" Velvet Lexan DURABLE. Labels have a 5 mil thick Lexan with a velvet surface and can last up to 3 years outside. SCRATCHPROOF. Labels have an anti-glare, textured surface that hides smudges, fingerprints and scratches. INSTALLATION. Labels have a 2 mil thick high tack adhesive and stick to plastics, wood, metal and, even, to rough or dirty surfaces.