Oh well,
The snake oil business of cutting nut slots.
This is a cheap file and you can cut slots with it, but it bends and its hard to get a straight cut.
Its cheap thats good.
But, cuts a course cut. I mean,
Its not worse than all the other files.
But honestly, after some deep googling old luthiers, the right tools for cutting nut slots are jewelers files and such. Completely round, fine, tiny rat tail jeweler files. Cuts a smooth completely round cut. But ofcourse nobody tells you that. Instead they sell you these wobbly course files that are virtially impossible to cut a straight round cut.
You can even get far with cheap chinese diamond round files on your usualy Chinese markets.
Cutting nut slots is not rocket science, theres alot of bull...
But if you practice you can cut your 0.12-0.16 slots with these.