Electronic system for acoustic guitar - 4-band EQ with built-in chromatic tuner, piezo ceramic pickup, Phase effect and feedback-fighting Notch filter. Device is equipped with high definition LED display that provides low battery message, Low/Middle/High controls, and Brilliance control for extended adjustment of highs frequencies (+/- 12 dB at 10 kHz). It also features 6.3 mm jack output. Powered by 9 V alkaline battery. Frequency response: 20 Hz-20 kHz. Dimensions: 52 x 54 x 4 mm.