The Atom LT Vest from Arcteryx is a proven performer. Elevated with advanced insulation and material technologies, this versatile vest delivers its best performance yet. Coreloft Compact synthetic insulation retains warmth even when wet and withstands years of packing and unpacking. The breathable, durable Tyono 20 shell resists wind and light weather, while the stretch fleece side panels aid ventilation and freedom. The entire vest even packs down into its own pocket, making it perfect for packing light and getting going.