12oz Whipcord Lightweight N1 Deck Jacket - Black IHM-48-BLKIHM 48 KHA Inspired by the classic US Navy deck jackets of the 1940s, Iron Heart's interpretation of the N1 has become a signature piece and for Fall Winter 25, they expanded the lineup with a new lightweight model. To achieve this, Iron Heart replaced the heavy wool insulation and quilted sleeves with a much lighter weather resistant Japanese Ventile cotton lining, slimming the jacket down, enhancing breathability and for a layer of protection