With three pieces it its Cloud Layering System, Sierra Designs separates your windproof layer from your waterproof-breathable layer, while promising warmth, weather protection, and versatility, all in a 22-ounce package.  When on the go, start out with the Cloud Windshell (6 oz.) made with 100-percent polyester with two-way mechanical stretch.  Add the 800-fill DwrDown Cloud Puffy (12 oz.) when you stop moving.  If it rains, add the two-layer waterproof-breathable Cloud Airshell (4 oz.), which packs down to the size of a few energy bars.