MusicNomad MN668 6 pc. Diamond Coated Electric Guitar Nut Slotting File Set - Light Strings, with Storage Case

These are fantastic nut files. The best I've used. The filing edge is rounded, like your strings are. The fact that these files have the rounded edge really makes all the difference in the world. I used them on 3 of my American guitars so far, a Gibson Firebird, a FSR USA Fender Stratocaster, and a 1966 Fender Coronado II. Being that these are premium American made guitars you'd think that the string slots would be well attended to. But a quick filing with this set transformed all 3 guitars, tuning wise. The tuners turn much more easily and smoothly now. They also seem to stay in tune much better too. Just from quickly filing the string slots. I knew that the files had worked from the first moment I turned the tuning peg, and it felt silkier, and more precise if that makes sense. It's now much smoother and faster to tune all 3 guitars. It seems like it added a bit of sustain too, while doing big bends. The notes live a little longer now. I was surprised at just what a difference it made. My point is if you think your guitars nut is good just because it's a premium grade guitar, you might be surprised. These file sets are great. Worth every penny. I really dug how you can quickly remove the file from each plastic housing if you want to. It was sorta awkward trying to get all the angles I wanted just right, but when you remove the plastic housing you can use the file part by itself and get right down in there. I was honestly sort of expecting to have to return these thinking they weren't gonna be worth it, but I not only am keeping them, I am now gonna get the other sizes I need too, bcuz these things paid for themselves the first use. I'd say it definitely added that much improvement with tuning and staying in tune. The case they come in feels really premium and durable as well. Very classy.