Superlight and incredibly packable. Worn as a midlayer or standalone. The lightest Atom vest offers summerweight insulation for early morning runs and evening hikes. The Tyono™ 20 shell is light, breathable, and wind resistant, and the Coreloft™ insulation is compressible, dries fast and allows airflow. Lightweight stretch fleece side panels provide ventilation and zippered hand pockets stash small essentials. All in a package that weighs about as much – and packs as small as – an apple.