Shadow ACP1 is a cable preamp for acoustic instruments with volume, bass and treble control. Shadow's cable preamps are unique in the music business! To make your original pickups active you would need to install electronics which is a major modification of your instrument. Shadow cable preamps will allow you to do this without modification. It will boost the volume, make your pickups low impedance and will allow you to trim, with additional active tone controls, your sound to the optimum. All cable preamps are powered by 9 V battery that mounts in the preampís case.