I wanted a case for my pittsburg precision screwdriver set similar to the ifixit cases. I like the gridfinity ridges to hold loose screws but didn't see the point for it to be holding the driver piece so i shaved that all down and tightened the model so it all fits snug when bouncing around inside the case. I added extra holes for driver bits as well. 

driver set linked below. 

https://www.harborfreight.com/33-piece-precision-screwdriver-set-93916.html?hftm_sc=189&hftm_source=google

I do not have an MMU3, so I did filament swaps to get the multicolor. My inner-shell fit super snug to the outer case and i had to hammer it a bit to fit so i suggest sanding or adding a tad to the model size depending on your printer tolerances. it all fits great now! 

Uses 6 3X30mm screws