Reliable insulation for long days out in the cold. The Jack Wolfskin Men's Helium Sky Jacket is a classic insulation jacket with a down fill. It is very light and packable yet also very warm. It also features a windproof outer fabric to protect you from wind chill and ramp up the insulation performance.The jacket's Stow Away function is also very practical. The whole jacket stuffs neatly inside its own hip pocket, creating a compact bundle that takes up very little space in your pack.