To make the women's Down Hoodie more suitable for high activity in the mountains, Salomon improved 2 key areas. First, we used a down-proof fabric that eliminates migration and loss of down over time. Second, we built it with a Smart Skin™ construction, substituting synthetic insulation under the arms and over the shoulders, areas where water typically builds. You get the best of both worlds: down's loft and packability, and the confidence of synthetic when you sweat.