The only information that I can find on Razex is that it was owned by a Mr Jucker from Herrliberg, Zurich.

This has a differential head and also the ability to use it in slant mode. As you can see it has a hook arrangement to attach the handle to the head. The little hook has a threaded section which allows you to tighten it. There are flats that will allow you to use it as a normal DE or a slant.
The underside of the head has 1 and 2 marked on each side which correspond to the different gaps.

There is a Swiss cross on the handle between the words Rasex and Combi. The bottom plate is cast so most likely Zinc. I can't imagine that the Swiss would have a shiny razor with one "non-shiny" piece so I suspect that the bottom plate was plated at one point, although I can't find any evidence of plating.

How does it shave?
Using it in normal "T" mode, I found it to be a very mild shaver even using its number 2 side.
It's slightly more effecient in "slant" mode, however I find that if I watch myself I compensate somewhat for the slant.
I definitely prefer using in normal "T" mode, it just works better for me!