I've seen comments about product made from Cuben material that highlights its breathability. Below is a quote from the Black Rock webpage, as an example of those claims (I've only heard good things about them, so I don't mean to be pointing fingers, just want to provide a reference). Can someone explain to me how that is possible since it is essentially high strenght fibers sandwiched between 2 polymer films? Is the final structure in those cases micro-perforated, or something?

"Designed to layer perfectly with the Black Rock Undermitts these pair up to create the lightest seam taped down insulated zero degree mitt system at 42grams. If you simply need the lightest waterproof breathable layer in your pack these mitt's are the answer."

Thanks,
Tom

check out the first item

http://www.zpacks.com/materials.shtml

this might help

Like a garbage bag.

John Abela's review

Oh, we'll, that certainly clears it up. It is the most breathable that John has ever used.

"Oh, we'll, that certainly clears it up. It is the most breathable that John has ever used."

lol. right..

So, it sounds like they replaced the polyester/Mylar films on each side with PTFE/Gortex. I would wonder about its increase in cost and decrease in durability. Any firsthand knowledge on that?
Thanks,
Tom