Thanks to my good friends in England I just received what could be the final Rotring Core Rollerball pen.The new one is the one on the left. It also turns out to be one of the prettiest of the set. The new one is the Rubidium red and black with the metallic red barrel. The two smaller blue ones on the right are the ball point pens.
This new Core is by far the hardest to find. Add them all to your collection.