· 100% Waterproof · Built with Seamless Construction - making them lighter and more durable · Constructed with 5.5mm Yulex natural rubber waterproof insulation and 2mm of air mesh for temperature regulation · Boot shaft easily adjusts to fit different size calves · Self cleaning, slip resistant BioGrip outsole · DuraFresh natural bio-technology activates to fight odors · Comfort rated to -40°F/-40°C · Bio-based footbed provides comfort while minimizing environmental impact