Bracket for a bottle. Fits on a IKEA Skadis Board.
Base on the Fusion 360 peg models from Rkimmell73 https://www.thingiverse.com/thing:3734897
50mm inside diameter
You can find the whole IKEA Skadis pegboard one my blog (article is in german): https://krisennerd.de/ikea-skadis-werkzeugwand
*** UPDATE ***
Added a version without the hole.
Der Autor hat die Herkunft des Modells noch nicht angegeben.