This is a nice stackable gridfinity case for the driver handle from the iFixit Mako kit, along with its flexible extension.

It's intended to go with a separate holder for the 4mm bits, such as my 3x2x6 labeled holder for 90 bits.

Prints without supports.

The case fits into the Gridfinity grid using a custom design inspired by @grizzie17's Gridfinity Refined and @rekk's Gridfinity Refried. You can push 6x2mm magnets in the nice press-fit magnet slots, or use a thumbscrew for a more permanent attachment. The thumbscrews printed from @grizzie17's files will fit this model, too.