This is a simple pen holder I designed so that I wouldn't keep looking for a permanent marker in my workshop.
This design uses 3 x 12mm x 2mm magnets. Two didn't seem to be quite enough. I glued them with super glue but araldite would be better.
I print it with the magnet hole side downwards and my Ender 3 manages to print this in PETG without supports.
pen_Holder-PartBody.stl | 232.2KB |