What is this?

Loks like a cape chain or something to keep a cape together…

Yes, also maybe used for a sweater. Clip it to both sides of something and let the chain fall across your front to keep the garment from falling off your shoulders. Women often used to wear their sweaters over their shoulders without putting their arms in the sleeves, and they might attach something like this to the two front portions to keep from losing the sweater. Did we call it a sweater guard? Yes, I think so. Once upon a time they were very cool, in a fifties sort of way.

Cape or sweater chain makes total sense to me! It has a pat number on it too which seems funny.

Anyway thanks I think you guys are dead on!

Looks like to fasten a man’s vest

@hungryhungryhortence yes, that might be it…