Arc'teryx Atom LT Vest Black - Men's - XL Arcteryx Men's Atom LT Vest Black - 2019 The Atom LT has non-locking zippers by design. One purpose of the non-locking zipper is that it is easier to operate with one hand. This design feature also helps to limit the possibility of damage to the zipper and lightweight face fabric directly adjacent to the zipper. Atom Lt Vest This sleeveless core-heater hugs the body with efficient Coreloft™ insulation to preserve warmth while smooth faced, air permeable, fleece stretch side panels increase ventilation. A wind and moisture resistant outer shell extends stand-alone usability. Atom Versatile synthetic insulated mid layers with a high degree of weather resistance. Lightweight High performance, minimalist design that is durable for its weight. Arc'teryx Essentials Versatile high performance designs for diverse activities and conditions. Synthetic Insulation Man-made insulation with quick dry times, durability and retains warmth when damp. This vest is in great used condition from a smoke-free home. If you have any questions, please leave me comment below.