Stanley 33-231 3-Meter x 1/2-Inch Heavy Duty Powerlock Tape Rule With Metal Case Die-cast metal case holds its own against rough handling Entire blade coated with heavy-duty Mylar polyester film for unbeatable durability Two-rivet, corrosion-resistant hook stands up to continuous use Special Tru-Zero hook does double-duty as a pivot for drawing circles and arcs Mylar is a registered trademark of DuPont Teijin Films for its polyester film. Only Dupont Teijin Films makes Mlyar polyester film. Limited Lifetime Warranty