-5mm Neoprene Provides Comfort and Flexibility with Shock Absorption and Heat Retention Properties. -100% Waterproof Flex-foam Upper with Four-way Stretch Nylon. -The Rubber Out-soles Provide the Most Stability All Season. -Breathable Airmesh Lining Allows Air to Travel Throughout the Boot, Keeps Your Feet Much Dryer Than Normal Boots.