It could be ANY German manufacturer or assembler but no proof tying it to any one exists as far as I know. Same for several other SS RZM makers.

If you troll back through this forum, you will see attempts to identify unknown manufacturers by the components, fittings and blade etches used. Since a lot of work was done by subcontractors and suppliers of fittings were many, these similarities may offer clues but no final ID in my opinion.

Dave