If Hobie has any stock on SX mains they will be dacron or pentex, not mylar.
The stock 18SX sails are the same material as the 17's sails - they're Mylar on one side and a Dacron taffeta on the other, with Dacron reinforcements at the corners.
"Pentex" sails are polyethylene naphthalate fibers (known by Honeywell's trademark Pentex®
) laminated between Mylar films. Dacron® and Mylar® are DuPont trademarks.
Dacron and Mylar are the same material (polyethylene terephthalate), but one is spun fiber and the other an extruded and stretched film.
Why would one wish to purchase a sail that is mylar/dacron laminate with all the issues that are known with that construction type?
The newer dacron fabric is much improved from the original but the cloth weight available is not as good as the older white Hobie dacron, white and colored is the same basic weight now.
I would seriously be surprised if the Hobie loft even had a SX sail available, they were unable to source a simple 18SE jib for me 2 years ago.
SX races open in most areas so why not run the fastest sails available?