The MTL Thermo Rogue 4 is the latest iteration of our elite winter hiker - our lightest, most athletic, most durable winter boot ever. Waterproof exteriors and 200 grams of insulation will keep you dry and warm for your typical cold-weather winter activities.Merrell MTL Thermo Rogue 4 Mid GTX Features: 200 grams Primaloft® Gold Eco Series synthetic insulation, Solarcore® insulation with Aerogel provides over toe and underfoot superior warmth while being extremely flexible and ultra-thin GORE-TEX® waterproof membrane, exceptional breathability and waterproof performance Vibram® Arctic Grip™ All Terrain outsole designed to effectively extend the winter traction season, due to the enhanced durability and versatility Vibram® traction lugs specifically designed to increase traction and shed debris with each step Bellows tongue keeps out debris 3D Print and TPU overlays on upper in wear zones for increased durability Molded TPU heel counter for security Gaiter D-Ring Snowshoe strap ridge for stability Cleansport NXT™ treated for natural odor control Rock plate for protection