Whether we have to clip it to our harness or stuff it in our pack, we always make sure that the Black Diamond Fineline Stretch Rain Shell is nearby. Black Diamond upgraded this jacket from the previous Stormline. This jacket is built for movement-filled adventures thanks to a packable design, 2. 5-layer BD. dry waterproof and breathable membrane, and strategic stretch. With this jacket we can climb, hike, and otherwise adventure despite the dark clouds.