Starrett C11H-6-4R Cast Iron Square Head With Satin Chrome Blade Combination Square, Black Wrinkle Finish, 4R Graduation, 6" Size With reversible lock bolt, scriber, spirit level Graduation: No. 4R - 1/8", 1/16", quick reading 1/32", 1/64" Cast iron head with black wrinkle finish Square blade easy-to-read, sharp graduation Bearing surface is accurately ground