I bought this Fret crowning file for a little project I started. Before buying his file I dodn't know a single thing about fret crowning, but watching a few videos on the net made be comfortable enough to begin the process myself. The file is great, and will quickly re-crown the flat fret tops. Just take it slow and don't use too much force or pressure. For the price it simply can't be beaten! As a starter file it's really good, but I think that once you get more advanced in doing this process, you should probably buy a diamond crowning file. That will give even better results, but for now this is fantastic!
A little tip: After re-crowning your frets, always remember to polish the frets with some very fine sandpaper. Micro Mesh they're called. That will make them look and play even better!