Featuring an 8mm neoprene bootie with fleece lining wrapped in layers of soft rubber so your feet will stay warm and dry in the most extreme conditions. The outsole features Vibrams all-new Arctic Grip A.T. with XS Trek Evo for advanced traction on all terrains including wet ice, snow, mixed/loose surfaces and hard pack. Technical description: 100% Waterproof8mm Neoprene Bootie for Comfort and Performance (5mm Mid)Fleece Lining for WarmthExtended Rubber CoverageLightweight Midsole for All Day Comfort and SupportbioDEWIXFootbed Insert Topcover with NZYMfor Odor Control and Moisture Management: Vibram Arctic Grip A.T for Wet Ice Traction Coupled with XS Trek Evo Adding Durability and Improved Grip on Wet and Dry Surfaces.