Thank you for your answers,
that's very interesting info!
I always thought that Tefi somehow bought and then used Kiraco manufacture as a base for its later models - looking at my Tefifon M540 chassis is almost like the one in Kiraco radios.
So it looks like it - Heinz Kisters started with selling radio kits in the first years of his small manufacture, then there was mysterious model Universum, then after two models bought from other companies he started small series in two seasons (1952-54) but he didn't see a possibility of keeping up with the 'big' competitors, so he joined Tefi. I hope am I right?
I would never guess that it was such small company, those radios looked quite good and definitely not amateurish.
Regards
Piotr