Wondering what these are for, box states- quantity 7, item crystal, plastic, stock no. FO36-7198396, ord. dept. no. A-7198396, mfr's no. 1770, used on watch pocket, Elgin,date packed Sept. 1950, inspected and accepted Nov. 1950, M. Kirkegard. Got these from LaRose back when they were in business. Is that metal ring on the crystal for shipping?
Gary

Crystal

I have used some of the war contract Elgin replacement crystals which were the "good" plastic but have never seen those metal rings.

Unless the rings are very thin, I expect they were intended to hold shape and protect the edge.

As a 1950 part, these could still be for pocket watches or the very versatile Elgin "Jitterbug" timer which was very widely used to time artillery flight time.