General Tools CF640MM Ultra Test Flex Steel Rule General Tools and Instruments CF640MM Ultra Test Flex Steel Rule, 150 mm, 13 mm Wide, mm and .5mm is a ruler is for machinists The markings are ultra fine black for easier reading and deciphering The rule is 150 mm long, and has a width of 13 mm The graduations of measure are mm and .5mm Features a plastic sleeve for added corrosion protection, and a hard satin chrome finish