evo.com | Arc'teryx Vests > The Arc'teryx Atom LT Vest is a quick way to add core warmth on those cool-but-not-cold-days, or for general winter use if you "run hot". Essentially the runaway best-selling Atom LT jacket without the sleeves, the Atom LT Vest features packable synthetic Coreloft | Arc'teryx Atom LT Vest 2020