Custom precision square 36" long X 18" deep X 3" wide

This is a custom machined square made from aged iron. I had this made to be able to send it into the field to be able to calibrate machinery. Unlike a blade square it cannot be bumped and thrown out of calibration. Also unlike granite squares it cannot be chipped or cracked.

The square has been ground and certified to grade [0]

The wooden box is 43" long (including handles) X 22" deep X 6" high.