Merrell Opti-Wick fabric transfers moisture away from your skin and dries quickly to keep you comfortable. 65% nylon / 35% polyester. 50+ UPF fabric. Interior tricot waist wicks moisture for dry comfort. Invisible side zip closure reduces bulk. Lightweight heathered fabric drapes just right, wicks moisture and dries quickly. Side slits offer walking comfort and mobility. Single welt button closure pocket. Single welt pocket with zip secure closure stores cash and other valuables.