Built to handle a range of environments – cold ones – the Thorium delivers serious warmth. Packed with 750 fill-power Responsible Down Standard certified grey goose down, it offers outstanding thermal performance for its weight. Down Composite Mapping strategically places Coreloft synthetic insulation in areas prone to moisture, the light, durable Arato 30 nylon shell has a DWR treatment for water repellency, a bio-derived liner reduces petroleum use, and the insulated adjustable StormHood adds even more warmth.