folding leather pocket magnifying glass

This little magnifying glass is 1-3/4" across, and folds into a brown leather sheath holder a little larger than that. It is stamped with initials "SA" on one side and "MADE IN U.S.A." on the other, the stitching that once held it together is now gone and it is a little pocketworn and dirty, a little green crud around the brass ferrule rivet that the silver-ish lens frame turns in and out on.

A nicely made little piece that will likely come in handy, probably 1960's-70's...?