Wittner GT30 Guitar Tuner with Built-In Mic Popular VU meters for easy visual tuning Built-In microphone for acoustic instruments Line-In and Line-Out with pass-through feature Battery check mode Notes: 6E (82.4 Hz), 5A (110.0 Hz), 4D (146.83 Hz), 3G (196.0 Hz), 2B (240.94 Hz), 1E (329.63 Hz)