The Atom Lt Vest Is A Proven Performer Across A Range Of Seasons, Landscapes And Activities. Elevated With Advanced Insulation And Material Technologies, This Versatile Vest Delivers Its Best, Most Versatile Performance Ever. Coreloft™ Compact Synthetic Insulation Retains Warmth If Wet And Withstands Years Of Packing And Unpacking, And The Breathable, Durable Tyono™ 20 Shell Resists Wind And Light Weather. Stretch Fleece Side Panels Aid Ventilation And Freedom, And The Entire Vest Packs Into Its Own Pocket.