This trim hybrid hoody is designed as an active-use insulation layer, providing vital core warmth with liberal mobility and breathability. Lightweight and compressible, the Atom LT Hoody features Coreloft insulation in the torso, arms and hood. The side panels and underarms feature Polartec Power Stretch with Hardface Technology, delivering stretch mobility and breathability. A wind and moisture resistant outer shell extends stand-alone usability. Fact: Every person at the Arc'teryx Head Office owns at least one Atom LT; most of the women have two. The reason? Coreloft insulation inside a light taffeta shell. All the comfort of a sleeping bag, but it feels weightless. The benefit of taffeta fabrics is their light, airy nature with an ability to turn aside wind. The Atom series have a taffeta outer lining that is treated with DWR (durable water resistant) finish to give them a long-lasting ability to shed moisture. DWR protects against light precipitation. Mid layers that can function as outer layers have varied degrees of weather shedding capability; they also have varied degrees of moisture management. In addition to being made of breathable Coreloft insulation, the Atom LT has breathable side panels of Polartec Power Stretch with Hardface technology to help regulate temperature during exertion. Highly compressible, Atom pieces pack down into a tiny parcel of stored warmth. Store the jacket inside its own pocket, or tuck it into a sleeve or inside the hood if you are not restricted by space. A quick shake restores the original loft, time and again.