The Womens Atom SL Hoody is an insulating lightweight jacket from Arc'teryx for women. The jacket is made with Coreloft insulation, consisting of lightweight, breathable, and warmth-efficient polyester fiber. The jacket is specifically designed considering the areas where insulation is needed, but balanced to suit milder conditions. With warmth comparable to a light fleece, but much lighter in weight, the Atom SL is an effective mid-layer in cool conditions and a good standalone garment when resting, starting early in the morning, or enjoying the view from a newly climbed peak.