NeilPryde Head Designer, Robert Stroj, explains the concept:
I have been thinking about this clew concept since my time at ART. After the introduction of the Compact Clew that came out on the RS5 at the end of 2004 I was hoping to be able to take this concept one step further and use all the advantages of the Compact Clew without having to compromise the outline of the sail.
The real advantage of this new concept is that there is a tension connection between the foot edge and lower leech. This helps to keep the foot of the sail from blowing out in gusts and also makes the whole leech twist, harmonically, getting even more out of the advantages already associated with the regular and Dynamic Compact Clew (improved lower leech twist and much reduced draft movement due to the lower leech ability to create reflex behind the boom which releases excessive power and effectively locks the draft forward).
In addition, there is the benefit of a cleaner sail outline, when compared to the Dynamic Compact Clew, and therefore better aerodynamics as it is not necessary to have a clew cut-out.