This is a very early WIP - I've tried to get measurements correct but I don't yet have the final item so it may be off. (let me know in the comments!)

Space for 16 bits, each space has a 5 x 2mm round hole for a magnet to be glued into, to hold each bit securely. (can buy these from Amazon)

Thinking of adding a couple of holes on each side for more magnets, to allow a modular design to stick boxes together for more bits.

Let me know what you think, what needs changed etc.

Print with at least 15% infill - the more the heavier. .20mm should be sufficient for quality.

PLA should be more than enough for this.