The iconic Atom is an Arc'teryx mainstay, whether as a midlayer or standalone garment, for a wide range of activities and performance levels. Over time, we've refined the design to elevate performance, improve durability, and expand its versatility. Its Coreloft™ Compact insulation retains warmth when wet and stands up to repeated packing and unpacking. Lightweight, soft, and durable, the Tyono™ 20 face fabric resists wind and weather, and the stretch fleece side panels enhance ventilation and freedom of movement.