Indigo Horse N-1 Deck Jacket (IN-1)First released in 1944, the N 1 had the longest service life in US Navy history as a much more functional follow up to the well known peacoat. We trace the history and influence of this garment over in our stories here if you want to dig a bit deeper. This iconic jacket is cut to hip length to retain mobility while maximizing warmth. All of the features were honed through 2 years of active warfare in WW2, including the button windflap over the zipper,