The rectangular bit bin was designed by Benjamen Johnson to accept the standard bit holders that come in the Milwaukee accessory cases (you can also purchase bit holders for non-Milwaukee brand bits). The bit bin comes with two rows of mounting holes and is made to fit the Low-Profile Organizer (48-22-8431) or the Compact Low-Profile Organizer (48-22-8436). The rectangular bit bin with a cutout can be used perpendicular to the standard orientation. The cutout allows the indents in the lid to clear the bit bin. To see an example of this use case, check out the gallery for the M12 rotary tool setup.
