NuDown revolutionised the way we think about insulation when it comes to clothing. Generally there are good products to keep you warm but usually the only thing that helps is layers. Not anymore. NuDown developed a jacket with air pockets that you can pump or deflate manually with a hand pump. The colder it gets the more air you put it. The air heats up from your body heat and the NuTeck technology takes care of the rest. You can exchange the air for Argon gas that has a higher heat capability. Extreme tech for the extreme cold, less all the bulk.