Looks sort of like a durometer tester, but without the right base. There is a starrett product number behind the needle. I can read NoX643 or NoX043. The last digit is hiding in the pictures you posted.
EDIT: Looks like is just No. 643, Starrett just calls it a depth gauge:
643J Dial Depth Gage
Note:<br/>This item is discontinued. Please consider the recommended alternative listed above or contact our special order department at (978) 249-3551 x410 for more information.www.starrett.com
Looks sort of like a durometer tester, but without the right base. There is a starrett product number behind the needle. I can read NoX643 or NoX043. The last digit is hiding in the pictures you posted.
EDIT: Looks like is just No. 643, Starrett just calls it a depth gauge:
643J Dial Depth Gage
Note:<br/>This item is discontinued. Please consider the recommended alternative listed above or contact our special order department at (978) 249-3551 x410 for more information.www.starrett.com
It definitely is a depth gauge, seeing that post of Xyphota.Can also be used to evaluate aircraft fuselage skin damage. Length, Width, and Depth of damage. Then off to the books.
Edit: That bar code on the back looks familiar. I may know where this unit came from.