Starrett C434-12-16R 12-Inch Combination Set with Forged and Hardened Steel Square and Center Head A choice of stable cast iron protractor - reversible is nicely finished with a black durable finish Graduation: No. 16R - quick reading 1/32", 1/64", aircraft quick reading 1/50", 1/100" With reversible lock bolts, scriber, spirit level in square, center heads and protractor head Direct reading double 180 degree protractor scale The square, center heads are forged hardened steel and cast iron reversible protractor with satin chrome blade, smooth black finish 16R Grad: Quick Reading 32nds, 64ths, Aircraft Quick Reading 50ths, 100ths Cast Iron Protractor Head Reversible Satin Chrome Blade