Summary

Leg extension for a vidaXL rattan lounge table like this one:
https://cdn02.plentymarkets.com/gtnsn41zax13/item/images/66259/full/vidaXL-4-tlg--Garten-Lounge-Set-mit-Auflagen-Poly-Rattan-Anthrazit-8719883785943-a-en-hd-1.jpg

The opening for the legs is 17mm x 17 mm and it's 20mm deep.
I suggest to print it diagonally (as shown in the pictures), otherwise the direction of the filament will allow the legs to break the piece when moving it around.