What is the difference between the Rotor 3D+ and the Rotor 3D-F?

There are 2 big differences:
– First, where and how they are made . . . . The Rotor 3D+ crank arms are CNC machined from solid (in Spain).  The Rotor 3D-F is first forged (Taiwan), then machined.
– Second, because of where and how they are made, the price is significantly lower for the 3D-F.