Thermoball clothing from The North Face is a really popular and great way of keeping warm. It is so light to wear and compresses down very small so ideal for taking in the rucksack for extra insulation when the temperature drops. The other great thing about Thermoball is the fact that it performs even when its got really wet so you don't get that chill factor if you get caught out in heavy rain. The Women's Zip In jacket will stow into its own pocket and can also be zipped into other The North Face compatible shell jackets to create an excellent winter combo, or worn by itself when walking or climbing. It comes with elasticated cuffs and a hem drawcord to keep the heat inside, two zipped side pockets and has front and departure logos to complete the look of this light and warm layer.