Spring Tempered Steel Rule with Inch Graduations, 7R Style Graduations, 36" Length, 1-1/4" Width, 3/64" Thickness. The Starrett 36" Spring-Tempered Steel Rule with Inch Graduation features a satin chrome finish. Graduations 16ths, Quick-Reading 32nds, 64ths, Aircraft Quick-Reading 100ths.