The Women's Arc'teryx Cerium Jacket is a down-insulated jacket for cold weather activity in the mountains. Hike days to extreme alpine climbs, this piece can be worn alone or layered with a shell. Featuring 850 fill down for an incredible warmth-to-weight ratio and combined with Coreloft synthetic insulation for those areas that are more likely to get wet, you'll stay warm when pushing the limits of adventure. When the weather shifts, the whole jacket packs into an included stuff sack for easy packing.