Mower Blade 18.87" long x 2.50" wide x .62"ID hole. CW. Flat blade - no rise/fall from mounting surface - bolt hole area to cutting edge. Very little lift edge at back of cutting edge. Length is measured diagonally.
Mower Blade 20.50" long x 2.50" wide x .75"ID center hole, outer holes .38"ID. CW. 1720679 supersedes to 1687014. This is part number 1720679 new OEM Simplicity.
Mower Blade 18.12" long x 2.50" wide x .75"ID hole. CW. New OEM. Serrated / Toothed Lift Wing. New OEM Simplicity part number 1721086. Blade stamped 1721086 Simplicity.