Here we have a DBX 120XP subharmonic synthesizer. For those of you yet to be enticed into the REAL lowend, let me blatently plagiarise the description fellow TB'er D.A.R.K. created to tell you what this thing does: "this unit is great in the fx loop to add earth shaking low end. not really an octaver, this generates a subharmonic waveform that is very musical. you have to be reasonable with it, you can shred speakers with this unit. the two bands of sub harmonics which you can adjust the intensity of are 24-36 hz and 36-56 hz. This is a great studio unit as well, cats like will lee and ronnie size sing its' praises, and it is used heavily in production for hip hop and drum n' bass. A little bit can help a bass really sit in the mix, i used it a bit more heavy handed for dub and dn'b production and live....for mixing foh, adding it to a subgroup for kick/toms and/or bass is great. Technically, it can also be a x-over for a pa, with stereo in/out and sub out options. There are a few versions of the unit out, but this particular model has given me the best results to date. a great tool for low-end junkies..." This unit is in good cosmetic shape with only a couple of rack scratches on the top, and works perfectly. SOLD!!. Come over to the dark side!! Thanks for looking!