The hot summer is coming to an end. That's why you want to carry the Atom, Arc'teryx's lightest weight, with you at all times. Its lightweight, compact design can handle sudden drops in temperature. The Tyono™ 20 outer shell provides a balance of breathability and windproofing. It also has a DWR finish to keep moisture at bay. Stretchable fleece side panels enhance breathability, and a low-profile hood helps you cope with changing weather conditions. When not in use, it can be buttoned up for compact storage.