This is a flag holder that I use at school with small but strong magnets glued to the bottom.  There is a square recess for them to fit into.  It should fit almost flush with five or so small magnets.  Double sided adhesive could be used as well.

Print Settings

Printer Brand:

Creality

Printer: 

Ender 3

Resolution:

200

Infill: 

20

Filament: Doesn't matter PLA or PLA+ or PETG Whatever Matches

Category: Office