. Professional guitar and bass tuner with volume, bass, middle, treble, and presence control knobs. LCD display for easy reading. Low battery check LED indicator. Auto and manual tuning modes. Powered by 6F22 9V battery (battery not included). Principle: Picks up vibrations through a piezoelectric strip, transmits signal to the host, amplifies via the host circuit board, and outputs to the speaker. This pickup is an active type. Specifications: - Frequency Response: 20Hz–20kHz - Control Range: - Bass: ±12dB at 60Hz - Middle: ±12dB at 500Hz - Middle 2: ±12dB at 1.2kHz - Treble: ±12dB at 3kHz - Presence: ±12dB at 8kHz - Mid2 Control: 600Hz–2kHz - Tuning Note: Chromatic and Guitar Mode - Chromatic & Guitar Tuning Mode (7B/6E/5A/4D/3G/2B/1E) - Pickup Type: Piezo Ceramic Color: As shown Material: Plastic Size: 9.8 x 5.5cm Package Contents: 1 x Pickup Kit Note: Product labeling may vary slightly between batches, but this does not affect functionality. Package includes only the items listed. Other accessories are not included. Note: Lighting and display settings may cause slight color variations between the image and the actual item. Measurement error allowed: ±1–3cm.