Flag holder for the diagonal metal bar on Thule Chariot stroller (might also fit other models). The flag I used measure ~7.7 mm in diameter, but the design can easily be modified to fit other diameters. (I specifically designed this for the Norwegian Constitution day, 17. May.)

I printed using black PETG from dasfilament (https://www.dasfilament.de/filament-spools/petg-1-75-mm/158/petg-filament-1-75-mm-schwarz?c=21), 0.2 mm Layer height, 30% Infill and enabling supports on build plate. Other settings/combinations will probably work fine as well