Print in TPU flexible filament 100% infill. It will take around 2 hours.
The large hole at the end can fit a 1/4" bit or as a place to hang it.
I designed this to hold 30 of the bits from the ifixit Mako kit that I only use very rarely, like the weird oval driver and the tri-lobe and penta-lobe bits.
It's ultra compact storage, but with 2 rows and my fat fingers, I need to use pliers to take the bits out. That's good for me, as I only use any of these bits ~3 times per year.
If you want more practical, single row 4mm bit holders for everyday use, see my other models.
The author remixed this model.
This holds 30 bits in 2 rows.