Durable, natural, hand-lasted rubber upper. Four-way stretch inner bootie doubles as the shaft. Built-in handles for easier on/off. 7mm waterproof Neo-Techâ"¢ insulation offers a warm, comfortable foot environment. Interior features DuraFresh bio-technology that activates to fight unwanted odors. Self-cleaning, non-marking, non-slip rubber outsole offers the traction needed for wet conditions. Comfort rated from temperate to -40°F or sub-zero conditions. 100%