From the brilliant ‘Artec’ company...This electro/acoustic instrument Equaliser / Pre-Amp is suitable for use with any instrument that is fitted with an electric guitar pick-up, electro acoustic transducer or piezzo pick-up. The Artec SE-EQ8 is an eight band equalizer / pre-amp offering plus or minus ten on 8 band widths ...Bass, Mid, Treble. also with slider volume control. With its wide input range and high impedence it can be used with many kinds of musical instruments. Because of low noise and high output, it can be controlled with a wide range of input signals. Takes a PP3 9 volt battery, but can be powered by a separate DC 9 volt power supply (not included) Please see below for more details...