This tray holds 32 bobbins of embroidery floss. I tested it with both DMC bobbins and some slightly thicker ones I had 3D printed and it works with both.
Ignore the seam in the photos, I ran out of filament while printing and haven't printed a second one yet.
It is available with and without hooks for use with Ikea Skadis pegboard.
Ikea Skadis hook by syfq91 on Thingiverse: https://www.thingiverse.com/thing:4964991
The author marked this model as their own original creation.