Tuning modes includiing : Greek-8 string : Most Common, 4-String Guitar Greek-6 string : European Tuning, Black Tuning Irish-8 string : Most Common, Octave Mandolin, Open D, Open G With auto noise filtering.First step is choose the frequency at top of screen, then choose the tuning at the middle of the screen. When you play instrument, the pitch will be shown on the panel for the individual string by indicating signal high or low. [Tuner] - A4 Frequency adjustment: choose 428~452 frequenci