Blade is lacquer coated for added rust protection. Durable key ring feature, trim and lightweight for convenience. The anywhere rule with you when you need it.From the Manufacturer1/4" wide blade is polymer coated for added rust protection. Durable key ring feature makes it easy to take anywhere. Convenient and lightweight. Mylar® is a registered trademark of DuPont Teijin Films for its polyester film. Only Dupont Teijin Films makes Mlyar® polyester film.