A few generations ago, Titleist offered the Matrix Ozik Xcon 7 shaft for driver and fairway.

In searching for this shaft I have come across the Matrix Ozik Xcon 7.1 shaft, the Matrix Ozik Code 7.1 shaft, the Matrix Ozik Code 7F shaft.

Presumably the last variation is for a fairway clubhead, but what is the difference between each of the first three shafts?

What sets "Xcon" apart from "Code" and why the nuance between "7" and "7.1"?