This part connects the wooden footman on Louet Wheels to it's front bearing/flywheel. The small ring you see to the right slides over the cone of the connector, clips into place, and holds the connector on the wheel. This also allows the connector to be released if the footman needs to be disconnected from the flywheel.
Connectors on older or used wheels often have a broken "collar" or ring that slides over the connector cup. This is the part to purchase, should your wheel have this issue.