With down in key areas, quick-drying synthetic insulation everywhere else, and breathable stretch panels under the arms, the Rab Men's Kaon Jacket blends lightweight warmth and moving comfort for alpine missions. The responsibly sourced, high-loft down insulation in the core traps your body heat and increases packability, while quick-drying synthetic insulation in weather-prone areas like the shoulders continues to provide warmth even when wet. To top off this performance-focused mountain jacket, Rab added flexible, non-insulated panels under the arms to increase breathability and range of motion when you increase your pace.