The NuDown is a jacket that uses inflation-assisted insulation to keep its wearer warm. The jacket is fitted with a hand pump that can be used to inflate the jacket to achieve the desired degree of core warmth, and a release valve that releases air to cool you down.
NuDown estimates that each pump increases warmth by about one degree Fahrehnheigt, with 20 pumps keeping you warm on chilly days and 30-40 pumps required for colder winter weather.
Perhaps the biggest challenge faced by NuDown had to do with keeping the jacket looking fashionable despite the air compartments and hand pumps required to make the inflation-assisted insulation mechanism possible. It seems to have overcome this hurdle with flying colors; this jacket looks modern and stylish and doesn't make you look like a potential arrest victim for the fashion police.