I originally gave it 5 stars, but also reported that the high (0.09) E string snapped right at the entry point of the tuner when I loosened the locking screw after installation. This now has happened 3 times to me with brand-new strings. I was extremely careful to tighten the screw to just the point when the E string did not slip anymore, while trying to tune. A careful inspection of the other (thicker) strings suggests that they have a nick in the metal, indicating that they are pinched/bent against a sharp corner, probably at the entry point of the strings into the tuner, where the screw pushes them upwards. Thicker screws and wound screws might survive this, but not the thinner strings.This is an unacceptable design flaw to have the risk of having strings potentially snap after a short while. So, for people like me who un- and restring their guitars or who must rely upon them for recording or live acts, or folks who like their string sets to last for a while, these tuners are definitely a no-go, although they are otherwise a really good product...My original review:Great quality and fit. The included hardware is heavy and of great quality. These went on a Frankencaster to replace those cheapo kit tuners. The fit was perfect.The tuning stability is fantastic. Even when pulling on the thinnest strings hard, they would not slip out. I must admit that I tightened one of the bare strings pretty tightly and it snapped. But then, it was an old string that he been on the guitar since a while. When putting a new set of strings on, I had learned my lesson (and trust in the locking screws) that I didn't tighten the strings too much. No tuning issues anymore...These are definitely a competitively priced replacement for any guitar coming with regular tuners. They are as good or better than average brand tuners.I was shocked how well the guitar stayed in tune (my guitars are in humidity-stabilized rooms, so the wood doesn't contribute that much to tuning issues). I plane to replace my regular tuners of all my 'working guitars' with these.