This is the acclaimed outboard room correction and crossover device by Peter Lyngdorf. Audiogon should have a better category for this than "equalizers", which does not do this unit justice.You'll be amazed at what you've been missing. Check out the reviews. This is a one-owner model in excellent shape. Used in a very high-end system and now being sold because I've spent $$$ rebuilding my listening room and no longer need this. microphone and extra-long microphone cable included. Please also check out my other listings, as I'm now selling several years' worth of extra equipment. Please email me for more info or with questions at firstname.lastname@example.org.