Stomp across the frozen tundra. Rubber(He) makes these Winter Boots as light as helium, 50% lighter than natural rubber, but as strong as iron. Plus, the 600-denier nylon uppers are waterproof. And an 8mm Thermal Guard liner keeps you warm on any frozen tundra down to -40 degree F. Waterproof 600-denier nylon uppers, rubber shell; Rubber(He) outsole remains flexible in all temps while also offering top traction; Removable 8mm Thermal Guard liner is also moisture-wicking; Adjustable snow collar with bungee lace lock; Hook-and-loop midfoot strap; Height: 14"; Weight: 31 oz; Mfg Number: NK0199.