Basic holder for 4 markers on classic white board.

4 rounded holes for neodym magnets (D8mm, 4mm height) + little bit of superglue.

Printed with 0,4mm nozzle, 0,3mm layer, supports: yes

Material what you like, i used PLA - Azure blue or Galaxy Black.

I also add a blender file if you want more modules, change the shape or size of the holes for other magnets or holes tight, without using instant glue