Paul B.wrote a review of Sierra Designs N2 Fusion Jacket - Men's on September 16, 2011
I guess what they call the 3rd layer is a fuzzy texture on the inside of the shell. This makes the jacket very comfortable and it doesn't stick to your skin like other jackets do. I wore this recently on a very warm humid rainy day with just a t-shirt on underneath. I was literally wore comfortable with the jacket on than off. The material just kind of sucks the moisture right off your skin. The jacket seems very durable too. I have the black which is more of a dark charcoal grey, but very nice.