This lightweight nylonÂ The North Face ThermoBall PrimaLoft Vest is outfitted with high-tech PrimaLoft insulation that offers the warmth equivalent of 600-fill down while maintaining performance in wet conditions. Wear it as a core-protective layer on the coldest days, or pack it along for lightweight-but-serious emergency protection on backcountry runs. $149. Free shipping. Buy here.