With a host of slush-busting features, they're built smart and built tough. A full 200 grams of heat-holding all-over insulation keeps feet toasty. KEEN.Dry.™ waterproof/breathable membrane blocks out moisture while letting vapor escape, so your feet won't feel like they're trapped in a sauna. The Thermal Heat Shield Footbed has an outer layer of wooly softness, a middle layer of support cushioning and a thermal foil barrier to harness radiant heat – keeps cold out and heat in. And true to Keen form, they offer superior cushioning and ankle support, with great traction to boot.