Satisfy Running's PeaceShell River Shirt is a technical play on the common trail running practice of wearing a flannel shirt. Trail runners would soak the shirt in mountain creeks as they run by to stay cool. This shirt is constructed from lightweight, fast-drying, 4-way stretch PeaceShell recycled micro twill from Japan. It also has ice pockets on the upper back for mid-race cooling. Weighs 168 grams.