It's an old Fichtel & Sachs design, from 70s or earlier. I think it came back to production few years back, now by Sram that bought Sachs while back. I think t

It's an old Fichtel & Sachs design, from 70s or earlier. I think it came back to production few years back, now by Sram that bought Sachs while back. I think there also is an old Shimano design, but that was 3 or 4 speed.