Carhartt developed Rugged Flex work boots for hard working men and women who demand extreme levels of comfort, durability and safety. Storm DefenderÂ® Waterproof Breathable Protection is designed to be completely waterproof and to keep your feet dry in most types of wet conditions with a waterproof and breathable membrane. FastDryÂ® Technology Lining wicks away sweat for comfort and the Carhartt PU with Foam cushion insole provides comfortable support and reduces foot fatigue. An EVA midsole with PU strobel pad provide extra layers of cushioned comfort. The Carhartt rubber Rugged Flexâ„¢ outsole is cement constructed. If you can't quit, YOUR BOOTS CAN'T EITHER.