I own several shade sails including one by Coolaroo. They are all made of a heavy woven synthetic fabric that allows water and some air to pass. The fabric of this particular sail has the same characteristics as covers made for exterior furniture and equipment ... it doesn't breathe and is water resistant. I just finished putting one up and couldn't help but notice the tendency to billow in the breeze. My other sails were gentling swaying at the same time, but this new one seems like it's ready to leave and take part of my house with it. On a positive note, I ordered two of these yesterday afternoon with 2 day delivery and received them this morning ... great service!
NOTE: These come with absolutely no hardware, not even cut pieces of rope. Once you've priced shade sail hardware, you'll have a better appreciation of the price differentials between different manufacturers.
