UGG's cuffable Butte boot is cold-weather rated to -20C and features waterproof bootie construction, warming insulation, and inno vative Vibram® outsoles designed to stay flexible in freezing temps. Rugged on the outside and cozy on the inside, it's made from waterproof materials and lined with soft, fluffy fabric. Enjoy the UGGpure™ wool for all-day wearability in the mountains or the city.