Don’t know, but judging from the shape of the fobs on each end (that’s what they’d be called if they were on a watch chain... smaller versions of course!) it looks like they were designed to pass through a hole, maybe in lumber or a board, then lock flat on the other side. Obviously intended to do the same thing on either end, so the length was intended to be fixed.
Maybe holding two component at a fixed distance on a pice of farm equipment or machinery. Or a removable chain on a buggy board or ramp?
Can’t wait to see what the expert who actually knows the answer will say!!!