This is 1/8" Bit holder with Collar made for my Carvera Air. Collar 7.6mm.
Large and small version.
Both have Numbers going out or inwards. Whatever is preferred.
For a single color printer the easiest is just to get the slicer to request filament change when the letters start with the outwards numbers model
This can be printet very hollow
I recommend the small one. I though I wanted more space between the bits, hence the large one was created.
The author marked this model as their own original creation.