Stormproof, designed by Coverking and made by one of the world's leading textile mills. It is the most waterproof yet breathable car cover material available. Stormproof car cover martial exhibits outstanding sun and UV resistance. The micro-fiber base material is soft to the touch and won't scratch a car's paint. Speak to somebody who has owned the other "premium" Car Cover materials and you'll hear how the other fabrics work as advertised for the first few months, but then degrade in their water resistance. The problem is that treatments and coatings can wear, scratch, or wash off. Stormproof is inherently water resistant. It has no coating, so it is very breathable. And the fibers have been designed to reflect UV rays, and be immune to the color fading caused by the harsh sun.
Check out the Coverking Car Cover Material Guide