Description of tech. drawings:
Dwg. shows a "box" with the top cover taken off revealing an assembly's intestines which often appear to be messily arranged:
- springs
- screws
- shafts etc.

and: a unique gear train

I'm never sure what "unique" really means in German in such a (not necessarily automotive) context:
- außergewöhnlich, einzigartig - mng. non-standard, unusual?
- eindeutig - mng. obvious, can't be mistaken for sth. else, can't be overlooked?

So far I have settled with "außergewöhnlich" and it hasn't been corrected yet but I'm not really happy.