Boss TU-3 Chromatic tuner

21-segment LED meter with brightness control
High-Brightness mode enhances meter visibility outdoors
Accurate to +/- one cent
Accu-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 six semitones below standard pitch
Tuner automatically mutes when the tuner is on
Supplies power for up to seven BOSS compact effect pedals
BOSS five-year warranty