SE-OE3 is the 3 band Equalizer - Bass / Mid / Treble. This is specially designed for Multi-Purpose Equalizer. This is originally for Piezo Pickup use, but with wide Input Range and High Impedance, it can be used for many kinds of musical instruments. Because of low Noise and High output, this can be used and controlled with wide range of Input signals. Specs: Bass : 100Hz, -10db ~ +10dB, Middle : 850Hz, -10db ~ +10dB, Treble : 4kHz, -10db ~ +10dB, Power supply: DC9V, Consumption: 4mA(active), 1mA(bypass), Dimension: 75.5(w) x 115.5(h) x 47.5(d) (mm), Weight: 320g (include battery)