One of the warmer women's Muck Boots has been upgraded for greater warmth and comfort. 5mm CR flex foam backed with a warm fleece lining. Boots will displace moisture effectively while keeping out the cold, damp weather. Rated to -40 degrees, it will keep you warm on the coldest of winter days. This rugged boot has proven durability and comfort enabling you to battle the snow, slush, rain or icy cold temperatures. Features: True women's last for superior fit and comfort, warm fleece lining, 5mm cr flex-foam, EVA contoured molded midsole, slip resistant rugged outsole, comfort insole, extened rubber exterior. Material: Rubber, Fleece.