This is a case for storing bits.
It can store bits with a seat of 6.35 mm.
It can store 20 of your favorite bits.
It can store bits up to 65 mm, or you can remove the spacer on the top and store bits up to 100 mm.
Modify the spacer according to your preference.

All parts other than the spacer are printed without assembly.

If the spacer is loose, use a 3mm screw and a 3mm insert nut.