This item is a fairly rare Polyphone Pro bass amp. It includes a single, lightweight speaker cabinet housing a 15" and 2x8" speakers. The amp head is a 3 space rackmountable unit that contains 2 separate amps each with their own preamp. Each preamp has bass, mid, treble, and volume as well as a bright-normal-dark switch. The amp can run in mono, stereo, and biamp modes. The crossover is selectable at 200, 400, and 800 Hz. There is an effects loop as well as a main out and individual preamp outs and power amp ins. This rig is hifi sounding and easy to transport. It is only 240 watts, so it is not extremely loud. If you use a low B string, I strongly recommend using the biamp setting as the 8" speakers do not respond well to loud low notes. (I have 2 of them - I'm keeping the more scratched up one as I love this amp). It comes with a "user manual" which is really just a few sheets stapled together, but it has all the info. you need. I also added screws through the front grill panels as they can shake loose and rattle. In lieu of sale, I will consider a trade for a 6 string (fretted) with fairly narrow string spacing.