The Thorium SV vest combines the exceptional warmth of a box walled down jacket with the freedom of a vest. This gives it a versatility to perform as an outer layer in dry, moderately cold weather, or as a lofty midlayer for more severe cold. Lofty 750 fill European grey goose down delivers exceptional warmth for little weight, is durably resilient, and packs easily. The vest’s baffles use box wall construction to deliver maximum loft. The outer is soft, durable Arato™ 40 nylon, a lightweight material that withstands abrasion, packs compactly and has a DWR finish to repel moisture.