12in Layout Square

12'' square has a 13'' outside scale, 12'' inside scale plus a 5'' scale on the bottom & 1 3/8'' on the ends. Outer rule is 16ths scale and has left to right and centering rule with small drilled holes every 1/16''. Inner rule is 32nds scale and has left to right rule with small drilled holes every 1/8''. Angle markings and drilled holes in the center from 5 degree to 60 degree in 5 degree increments plus a 22.5 degree. Aluminum base with blue anodized finish is 1/2'' tall and blades off set at 1/4'' and 3/8'' and a 45 degree cut out. Squareness: 0.0002'' per inch. Laser engraving on both sides of 2 mm blades. Sets include a mechanical pencil and lead refills. Supplied in protective box.