Starrett C11H-18-16R Combination Square with Cast Iron Head and Black Wrinkle Finish With reversible lock bolt, scriber, spirit level Graduation: No. 16R - quick reading 1/32", 1/64", aircraft quick reading 1/50", 1/100" Cast iron head with black wrinkle finish Square blade easy-to-read, sharp graduation Bearing surface is accurately ground Cast Iron Head with black wrinkle finish 18-Inch Starrett no glare satin chrome hardened steel machine divided blade Reversible lock bolt, spirit level and scriber Graduation is Quick Reading 32nds, 64ths. Aircraft Quick Reading 50ths, 100ths