Need a preamp for your acoustic guitar pickup but don't want to install batteries or preamps into the side of the instrument? Here is the unit--Discrete Pure Class A FET input Preamp that makes any pickup sound better! 9V phantom power for mini-mics, eliminates the need for battery on guitar and belt clip to attach to strap or belt. Features include Treble, Bass, Trim, and Volume. Phase invert switch with In and out connections, and finally a gain trim to match any input you need to connect to.