Alpina Alaska 75 mm backcountry boots are bold firmly and seriously. Alpina modeled them after rugged hiking boots with durable leather and synthetic uppers which protects our foot from the elements and gives the boot moderately rigid flexibility providing sufficient control during ascent and descent. For added protection, Alpina has integrated a waterproof and breathable Alpitex membrane into the boot so that during long trips our feet do not get wet and also included Thinsulate insulation to keep your toes warm when we make our way through the wild forest and along an impassable road. fields.