Spring Tempered Steel Rule with Inch Graduations, 7R Style Graduations, 48" Length, 1-1/4" Width, 3/64" Thickness. The Starrett 48" Spring-Tempered Steel Rule with Inch Graduation features a satin chrome finish. Graduations at 16ths, quick-reading 32nds, 64ths, aircraft quick-reading 100ths. 48", 7R Grad 100ths.