TOM'SLINE Mini Foot-operated Guitar Effects Pedal Tuner 1. Material: aluminum alloy 2. Tuning mode: semitone 3. Pitch range: 430-450Hz 4. Flat: b, bb, bbb, bbbb 5. Adjustment tolerance: +-0.5 cents 6. Power supply: AC Adapter 9V DC (Not Included) 7. Full metal shell, sturdy and durable 8. Tuning pedal, suitable for stage and studio 9. A4 is pitch button, flat is flat button 10. Screen displays note name, tuning table and calibration, pitch and flat 11. Output jack: 14" mono audio jack for signal output 12. Input jack: 14" mono audio jack for connecting guitar 13. Size: 9x3.8x4.8cm 14. Weight: 131g How to Use: 1. Connect DC 9V Power on the pedal 2. Connect the input and press the ONOFF button to turn on the tuner 3. If you want to change the pitch, press the A4 button, the pitch range is from 430Hz to 450Hz 4. If you want to tune by flat, press the Flats button, Flats provides 4 steps: b, bb, bbb, bbbb 5. Play a note with the guitar, the note name will appear on the tuner screen. The screen color will change and the tuning needle will move - The central blue tuning meter appears, and 2 blue triangles appear: the note is in tune - The left red tuning meter appears, and the left blue triangle appears: flat notes - The right yellow tuning meter appears, and the right blue triangle appears: sharp notes. 6. The tuner has a bypass function. After tuning is completed, press the ONOFF key, and the original guitar signal will pass through without distortion.