300mm - 11-3/4" Spring-Tempered Steel Rule with Millimeter and Inch Graduations, 32nds and 1/2mm on One Side; 64ths and mm on Reverse. The Starrett 300mm - 11-3/4" Spring-Tempered Steel Rule with Millimeter and Inch Graduation features a satin chrome finish. Graduations at 32nds and 1/2mm on one side; 64ths and mm on reverse. 300mm (11 3/4"), No. 36 Grad.