The North Face Men's Thermoball Bootie II fabric Upper: Durable, water-resistant, element-shedding, 100% recycled P.E.T. ripstop upper Upper: PrimaLoft ThermoBall insulation, which offers the lightweight warmth of down with the wet-weather insulating performance of synthetics Upper: Internal gaiter with adjustable drawcord keeps snow and debris from entering the boot Bottom: Cushioned, abrasion-resistant, injection-molded EVA midsole Bottom: IcePick temperature-sensitive rubber pods for increased traction