There have been many different versions of the Vitalizer, I believe this one to be one of the first ones, it is in very good condition and works well.
It is very well made and has unbalanced inputs and outputs on 1/4" jack.
The controls are Sub Bass, soft or tight, Peak led's, Mid High Tune, Harmonics, Process Min to Max there is an active switch for these controls. there is also an active switch for a Surround Processor On/Off Switch. It is an interesting effect.