What might this be? 

It is stamped with   "MAOSTER"  inside of what look like a graphic of a wedding band

Small hand tool with a wing nut operated jaw,  jaw notched maybe for small wire,  handle is hollow allowing wire to pass thru?

See attached.




Thanks
Rod

it looks like a pin vise.

but the name MAOSTER ???

Jeweler's hand vise

Looks to me like Mauser.  I know they made a quick adjust wrench, but that's the first jewelers vise I've seen.  Very nice!

Mike

It is Mauser-

Could MAUSER make it a gunsmith's vise?