With a host of slush-busting features, KEEN® Revel IV Polar Boots are built to tromp all over winter. A full 200 grams of heat-holding all-over insulation keeps feet warm toasty down to a teeth-rattling -25°F. 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 woolly 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, toe room and ankle support, with great traction to boot. Last but not least, the leather is sourced from a Leather Working Group-certified tannery, so you can feel good about treading more lightly on the environment, too.