Starrett 434-12-4R 12-Inch Combination Set with Forged and Hardened Steel Square and Center Heads Cast Iron Protractor Heads Reversible 4R Grad: 8ths, 16ths, Quick Reading 32nds, 64ths with regular finish A choice of stable cast iron protractor - reversible is nicely finished with a black durable finish Graduation: No. 4R - 1/8", 1/16", quick reading 1/32", 1/64"