Sorel M Caribou Reserve Bt This year, our premium take on the Caribou comes wrapped in luxuriously soft, durable bison leather & topped with a sleek shearling snow cuff. Features Seam-sealed waterproof construction with full grain bison leather upper Shearling snow cuff Removable 9mm felted wool & shearling Inner Boot 2.5mm bonded frost plug Handcrafted waterproof vulcanized rubber shell with Sorel Aero Trac non-loading outsole Additional removable 6mm felt liner included Imported