The file 'Gridfinity Big Marker Holder 3D Printer Model' is (stl) file type, size is 200.8KB.
I couldn't find a marker holder that could hold expo markers so I made one that alternates with normal marker sizes (12 mm) and expo sizes (20 mm). I staggered it to make a bit more space.
Bigger_Sharpie_Holder.stl | 858.6KB |