Just the best tuners I ever bought, up there with the Grover locking tuners in terms of quality and stability, and outstanding look.
I discovered when I put these on different guitars they truly hold the tuning after big bends. (given the nut is lubbed. Just for the heads up as I normally don't think tuners improve intonation but somehow with these is different.
The string cutters work perfectly fine too, is stupidly fast to change strings.
It will work on any standard guitar headstock but not right away on a vintage model as their headstock is thicker. The upper thread doesn't work as in a normal tuner, these are a single unit with one washer and nut from the top, no shaft.
Therefore the unit has less moving parts and feels solid. No play or wiggle.
These are slightly thicker than a normal tuner when you insert them from the bottom, they fit super tight, even needing a couple hits with your hand.
So be careful and sand a bit any excess lacquer on the top cause the tuner will catch on it and chip it. Happened to me, luckily I could cover it with the washer.