1、A4 for pitch button. 2、Flat for flat button. 3、Screen shows note name, tuning meter and calibration, pitch and flats. Features: Full metal shell, durable and exquisite. A4 for pitch button. Flat for flat button. Screen shows note name, tuning meter and calibration, pitch and flats. Output jack: 1/4" mono audio jack for signal output. Input jack: 1/4" mono audio jack for connecting guitar. True bypass footswitch design. How to Use 1. Connect a DC 9V power into the pedal. 2. Link the input, and turn on the tuner by pressing on ON/OFF button. 3. If you want to change the pitch, then press A4 button. The pitch ranges from 430Hz to 450Hz. 4. If you wish to tune by note flat, press Flat button. Flats offer 4 steps: b, bb, bbb, bbbb. 5. Play a single note from your guitar, the note name will appear in the tuner screen. The screen color will change, and the tuning needle will move. The center blue tuning meter appears, and 2 blue triangles appear: note in tune. The left red tuning meters appear, and the left blue triangle appears: flat note The right yellow tuning meters appear, and the right blue triangle appears: sharp note. 6. The tuner has bypass function. When tuning finished, press ON/OFF button, the guitar signal will get through without any distortion. Specifications: Model: AROMA AT-07 Material: Aluminium Alloy Tuning Mode: Chromatic Pitch Range: 430-450Hz Flat: b, bb, bbb, bbbb Tuning Tolerance: +-0.5 cent Power supply: AC Adapter 9V DC (not included) Item Size: 9 * 3.8 * 4.8cm / 3.5 * 1.5 * 1.8in Item Weight: 131g / 4.6oz Package Size: 12 * 7 * 6.5cm / 4.7 * 2.7 * 2.5in Package Weight: 223g / 7.8oz Note: Please use the 9V power adapter whose polarity is positive pole outside and negative pole inside. Otherwise, the product may not work properly. Package List: 1 * Chromatic Tuner 2 * Adhesive Tape 1 * User Manual (English & Chinese) 1 * Hardcover Box 1 * Chromatic Tuner 2 * Adhesive Tape 1 * User Manual (English & Chinese) 1 * Hardcover Box