Vintage Starrett Depth Gauge & Protractor No. 236 Athol Mass USA

Description

Vintage Starrett Depth Gauge & Protractor No. 236 Athol Mass USA.
I purchased 3 vintage compasses and this item in a box at an estate sale as a joke for my son who has asked a few times  if I have located the "good" compass he left behind more than a decade ago (I have not).   This is exactly as I found it with no attempt at cleaning.  I believe the original owner etched his name on the wider area - this can be seen in the photos.  Seems to be in good shape, neither pristine nor filthy or bent.  I hope the pictures tell the story because I am not familiar with this item.  I copied the title from an old Ebay listing which looked the same but just a different model number.
Please review photos carefully and request more if needed.  Questions always welcome!