evo.com | Arc'teryx Midlayer Vests > The Arc'teryx Atom Vest delivers core insulation with unrestricted shoulder movement, making it ideal for technical climbs or long hikes where you need warmth but can't sacrifice mobility. The synthetic Coreloft insulation performs even when wet, giving you reliable warmth for high-output adventures year-round, whether worn standalone on cool days or as a midlayer under shells when conditions turn nasty. Regular Fit A classic fit is cut comfortably throughout the chest, waist, hip, and thigh. It allows freedom of movement, provides shape, and layers comfortably over or under our layers. Articulated Patterning Synthetic Insulation Coreloft(TM) 60 g/m^2 100% Polyester No Slip Zip(TM) Front Zipper Performance Stretch Fleece Side Panels | Women's Arc'teryx Atom Vest 2026 - Large Purple | Polyester