Often imitated but never equaled, Sorel's Caribou is the true icon with a nubuck leather upper, waterproof seam-sealed construction, and a removable felt inner boot for warmth, comfort, and protection in cold, wet winter weather. . Comfort rated to -40degF/C for extreme warmth. Removable, insulating 9 mm washable felt inner boot with two-layer construction:~ Polypropylene and recycled polyester wick moisture and trap warm air~ Reinforced seams and heel area for exceptional durability~ Stretch front shaft ensures comfortable fit and seals cold air out~ Sherpa Pile snow cuff to keep snow out. Aero-Trac rubber outsole and nonloading lugs for sure-footed, slip-resistant traction on snow and ice. 2.5 mm bonded felt frost-plug midsole increases thermal barrier between your feet and cold ground. Seam-sealed waterproof construction. Waterproof nubuck leather upper for protection and durability. Handcrafted, waterproof, vulcanized rubber shell to keep feet dry. Shaft height: 10 in. (25.4 cm).