Gridfinity screwdriver bit storage.  This fits in the left front corner of my Craftsman toolbox (see the cutout in the side).  Gridfinity base squares are 42mm, otherwise used the Gridfinity Design Reference sheet.  I found that the 41.5 x 41.5 didn't fit my base squares.  For those who have issues with their gridfinity prints curling up on the corners, I used a smooth print plate and 65c bed temp.