Found among dive gear while going through old stock in a marine store. Also near fishing gear. No idea.
A: This is a repair tool or a jig/fixture for disassembling/reassembling an “omni-swivel”. It is an aftermarket 360-degree swivel used on scuba regulators. The fixture helps hold the oddly shaped bits. I’m a scuba repair tech and have two in my workshop.
It’s used for covering the Sabbath bread in Jewish culture.
(Aaaaaaamd start the racist comments because this is the internet.)