These winter boots are extremely durable, comfortable and warm! These boots are made from a water-repellent 600 denier polyester canvas outer upper laminated to moisture-wicking foam, as well as an inner layer of fleece on the upper and foot, which creates an air layer insulated designed to provide extreme comfort in cold weather situations. The multi-layer wool insulated insole also has an aluminum foil heat shield on the bottom for added warmth. Water-repellent outer upper. Outer shell treated with Teflon to keep your feet dry! Multi-layer insulated insole Aluminum heat shield on the bottom 200g 3M Thinsulate insulation, rated to -20C.