Built to withstand severe cold without weighing you down, the Thorium Jacket leverages high-loft 750 fill-power goose down for maximum thermal efficiency. Arc’teryx combines natural loft with Down Composite Mapping™, placing synthetic insulation in high-moisture zones to protect your core heat in unpredictable weather. Finished with an abrasion-resistant, weather-treated shell and an insulated StormHood™, it delivers uncompromising protection whether layered on the trail or worn solo around town.