Warmest, thermo-mapped Atom for cold, mid-output mountain activities. When the cold hits hard, reach for our warmest Atom jacket. Built for winter hikes and above-the-treeline adventures, it delivers breathable warmth in frigid, damp, and windy conditions. Synthetic Coreloft™ insulation seals in heat, while female-specific underarm gussets boost breathability where you need it most. The cornerstone of your winter hiking kit, the Atom SV serves as a standalone and rides comfortably under a hardshell for next-level protection.