A simple gridfinity holder for needle file booklets. None of the current gridfinity models suited my situation so after a few minutes on TinkerCAD I made this. 

The large slot is dimensioned to fit the Harbor Freight needle file set Part No: 69876

The small slot is dimensioned to fit a no-name brand set, but it should fit most booklets that are similar in size. It should work with Harbor Freight Part No: 56743