Boss AD-2, Effects Pedal, Preamp for electro-acoustic guitars, Acoustic Resonance reproduces the complex resonance characteristics of an unamplified tone, Ambience adds reverberation that is perfectly optimized especially for acoustic guitars, Notch filter for feedback control, Controls: Ambience, Acoustic Resonance and Notch, Power consumption: 55 mA, Power supplied via 9 V battery or 9 V DC power supply (coaxial connector - negative polarity inside, not included, corresponding power supply device: Article Nr #409939#), Dimensions (W x H x D): 73 x 59 x 129 mm, Weight: 450 g