For the price I paid (on clearance), the hat is a…
Fabric: nylon, membrane (like Gore-tex), polyester wicking
Price Paid: $3
For the price I paid (on clearance), the hat is a steal. I bought two. Marmot always uses top quality fabric and construction.
The rain membrane goes down the center of the cap and is about 6 inches wide. The sides of the cap are vented and have no membrane. The cap is good looking also IMO. Wicks moisture well.