Dreizack Solingen... Interchangeble Toolkit

I have this interchangeble 11 piece toolkit in a folding leatther case , Dimensions are 5x4.5 with two snaps, it is in excellent condition, I am trying to find out if anyone could tell me the value of it, if somebody out here familiar with such an item. I don't know when the item was made, the only markings on the leather case is the Solingen logo" which looks like a pitchfork". I would appreciate if someone could be helpful in giving me some insight on this item. I have included 3 photos. Thank you very much.