Pentex isn't really famous for anything, mostly probably because it lives in the shadows of its more famous siblings, carbon fiber and aramid. In sailcloth, Pentex is used as an alternative to aramid when class rules don’t allow that material. Where Pentex especially shines is in its ability to withstand lots of folding and bending with very little effect on the integrity of the fiber, otherwise known as minimal “flex loss.” Odds are you've never heard of it, but it won't disappoint.