Keson MC18M50 Closed Metal Housing Fiberglass Measuring Tape (Graduations:  ft., in., 1/8 & m, cm, 2mm), 15M/50-Foot Metal Crank handle to provide years of rugged use Heavy-Duty 1/2-Inch blade with 40,000 strands of fiberglass ensures a long life under the most demanding field use Double-Throat rollers guide the blade return and prevent the tape from twisting Closed, metal housing protects the tape Ultra-glass blades with 42 strands of fiberglass ensures a long life under the most demanding field abuse