The Arc'teryx Women's Thorium SV Down Hooded Jacket adds a whole lot of warmth to your mid winter and shoulder season adventures. Instead of aimlessly stuffing the Thorium with down or synthetic insulation, the jacket uses both with 750 fill down throughout the body and Coreloft synthetic fibers in areas prone to moisture. Since the jacket is mainly filled with 750 fill down insulation, the Thorium maintains much of the same compressibility and loft that has made down a staple in mountain activities for decades. The durable nylon fabric is treated with a DWR coating, so light moisture from snow and mist will bead up and roll right off the jacket. The Thorium is designed to be worn on its own, which is why it features a box wall baffle construction, delivering maximum loft and increased warmth.