The evolution of one of Merrell's most successful winter boot franchises ever. The waterproof construction and Vibram Arctic Grip underfoot with keep you dry and deliver traction in any conditions mother nature can throw at you. With 200 grams of insulation and a fleece lining your feet will stay warm when the temperatures dip. FEATURES: Waterproof membrane seals out water and lets moisture escape Heavy-duty, Waterproof, YKK zipper for easy on and off 200 grams synthetic lightweight, low bulk insulation for warmth and comfort Solarcore(R) Aerogel insole provides underfoot superior warmth while being extremely flexible and ultra-thin Cleansport NXT(TM) treated for natural odor control Merrell Air Cushion in the heel absorbs shock and adds stability Super Rebound Compound midsole provides durable shock absorption to help reduce torque and allow for a smooth transition into the midfoot Vibram(R) Arctic Grip(TM) All Terrain outsole designed to effectively extend the winter traction season, due to the enhanced durability and versatility Vibram(R) XS Trek Evo outsole designed to provide optimal balance of traction and flexibility on wet surfaces