This is a remix if the inner portion of my original model. This one is intended to be printed with rigid filament (PLA, PETG, ABS, etc.). It has the corresponding number of holes on the bottom to insert 6x3mm magnets for bit retention. The tolerance around the bits has been loosened a bit so that they can easily be pulled in and out, but still kept in place with the magnets.
Just download the model for the number of bits you want to store, insert the magnets and download the corresponding case shell from here:
https://www.printables.com/model/272857-ltt-screwdriver-bit-holder-multiple-sizes
The author remixed this model.