Retaining furnace level heat when the mercury dives into teeth chattering territory, the Burton Men's AK BK Down Insulator Jacket keeps you warm in the coldest conditions imaginable. Its 800 fill down insulation efficiently captures body heat when you're riding in sub zero temperatures and walking through Arctic like blasts of cold air. Another major benefit of down, its highly compressible fibers make for easy stashing within your pack. Keeping outside moisture from compromising the down's heat trapping loft, the jacket's lightweight 20D ripstop shell features a DWR treatment that repels light rain and snow showers. Fleece lined hand warmer pockets keep your digits from freezing solid in exceptionally brisk conditions. Furthermore, the zippered underarm vents quickly expel built up heat and perspiration, should the temperature rise throughout the day and leave you a bit too hot.