Daddario PW-CT-12 Micro Headstock Tuner

This is a very good and also a very affordable micro size tuner, suitable for many different instruments. Due to the low price I have on of these on practically every guitar I own, so I never have to look for a tuner, cause it's already there! Placing is almost never a problem, it is very discrete when placed on the back of a head stock. Display is simple but to the point, it shows you what you need. I use it on everything from acoustic and electric guitars to bowed instruments and folk music style plucked instruments. It triggers surprisingly well even on lower tunings, I use it all the way down to a low G (9 semitones below a standard guitar bottom E) on my long scale folk music style 12-string guitar. The only downside from my point of view is that the battery life is a tad short compared to other micro tuners, though still not over all bad. I've also found that when the tuner signals low battery, it still runs a decent amount of time after that.

I have one of these on all my instruments. Small and easy to use and very visually unobtrusive. This new version with the rubber buttons are a great inprovements as the older plastic ones would rattle and buzz when playing.

Only drawback is that it has some trouble with lower frequencies. Anything lower than an E on acoustic instruments I have to use the 12-fret harmonic for it to register the note.