Used BOSS TU3 Chromatic Tuner Pedal

21-segment LED meter with brightness control High Brightness mode enhances meter visibility outdoors 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 6 semitones below standard pitch Signal is automatically muted when the tuner is on Supplies power for up to seven BOSS compact effect pedals (with optional PCS-20A cable, sold separately)