This piece is used to grab (it is a handle) the blinds of some caravans (blackout curtain/blind).

It is slided in from the side, and you can grab the plastic handle or the ring to use it. There's a hook at the bottom that can be used to grab the ring and prevent it from rolling up. Not sure what kind of brand it is, but there are some similar parts in caravan supply sellers.

Attached the FreeCAD file in case you wanna tweak it or improve it.