The North Face Men's Thermoball™ Lifty II Winter Boots offer the most revolutionary insulation technology and are ready for any rugged, snowy trail. These boots feature the warm insulation of ThermoBall™ technology, which was developed in partnership with Primaloft, Inc, that unlike traditional continuous-filament synthetic insulation, the small, round PrimaLoft® synthetic-fiber clusters closely mimic down clusters, trapping heat within small air pockets to retain warmth. These boots also offer the best traction and comfort for your feet and offer a classic yet innovative style. Whether you're hiking snowy hills, ice fishing, or manning the lifts, your feet will be safe and warm in these rugged, waterproof winter boots with heavy duty (400 g) PrimaLoft® insulation and temperature-sensitive soles for superior traction.