As light as freshly fallen snow. But much warmer. Jack Wolfskin Helium the is a classic insulated jacket with a down fill. It's very light, super warm and packs down small. The STORMLOCK outer fabric shuts out the cold wind, thereby increasing the insulation performance.The jacket's stowaway pocket is a very practical feature. The whole jacket stuffs neatly inside its own pocket, so it takes up very little space in your pack.