Boss TU3 Chromatic Tuner Pedal Guitar and Bass Tuner Pedal with High-Brightness Mode for Outdoor Visibility, 21-segment LED Meter, Drop Tuning Support, and Guitar/Bass Mode Stompbox-style guitar tuner pedal21-segment LED meter with brightness controlHigh-brightness mode enhances meter visibility outdoorsAccu-Pitch sign function provides visual verification when tuning is complete Chromatic and Guitar/Bass mode (tune by string number, with support for 7-string guitars and 6-string basses)Flat tuning is supported with Guitar Flat mode, which allows for Drop tunings up to 6 semitones below standard pitch