This fits up to 55 bits (long bits excluded), the WOWStick itself and the magnetizer/demagnetizer.

This was drawn as the other alternatives were not working for my use case.

You will need to hot glue 8 magnets to the corners (Size 5mm*20mm*2mm), be careful of magnet polarity when doing this. 

Used standard 15% gyroid infill with 2 outer perimeter lines (works well on jetblack prusament). Maybe increase the outer perimeter lines in case you use transparent filament.