Acoustic Guitar Pickup, 2-Band EQ with Phase, 2.2 milli-ohm Input Impedance, Frequency Response: 20 Hz – 20 kHz, Bass Control Range: ±9 dB at 100 Hz, Treble Control Range: ±9 dB at 10 kHz, Battery Life: 700+ hours, Power Supply: 9V Alkaline Battery, Low Battery Check LED, Function: Phase S/W for anti-feedback, Pickup B-7500 (piezo ceramic), output jack: 6.35 mm (1/4”), dimensions: 61 x 40 mm (2.4” X 1.57”).