Klein and Hummel SA600

I have this Amp that was given to me and cant find a thing about it. Does anyone know if it's any good or the approx worth? I've been holding onto this amp because its from my late father, but running out of space. Any help is appreciated!
This is a Klein and Hummel Telewatt SA 600
you can find the original manual (sorry only in German):

This power amplifier is one of the best ever made. It was developed by a young engineer under the direction of Reinhard Wieschhoff at KLEIN + HUMMEL in the late 1970's.
You should keep it as there are not that many produced - some in the lower hundred pieces only.