Men's Korsa Vital 1/2-Zip: The Vital 1/2-Zip is built for runners who want a layer that adapts as quickly as the weather does. It gives you lightweight coverage for cool starts and changing conditions, while the half-zip construction makes it easy to vent heat once your body warms up. The fit stays athletic without feeling tight, and the fabric moves comfortably through each stride. This is the kind of piece that earns year-round value because it bridges the gap between too warm and not warm enough.