Korg GT120 Chromatic Guitar and Bass Tuner Dedicated chromatic tuner for guitar and bass that supports seven-string guitars and six-string basses. Dual display combines a needle-type indicator with an easy to read backlit LCD screen. Choose from two tuning modes: Auto or Manual. Built-in reference tone plays in a 5 octave range. Flat Tunings: 1-4 in half-note steps.