When you're looking for a guitar tuner that will fit in your pocket, you simply can't go wrong with the Korg GA-2. Korg is a known leader in ultra-stable tuner technology. And here, with the Korg GA-2, they've updated their popular GA-1 with some convenient features. You get the superior accuracy Korg tuners are known for, complete with adjustable calibration, a wide range of pitch detection, and helpful reference tones from the internal speaker when you need them. Better yet, the display has been enlarged to be much easier to read. And with 200 hours of continuous use via the battery, you can tune for days.