This version of Sorel's Caribou features a wool inner boot to keep feet warm, dry, and cozy during activities in winter weather, along with a full-grain leather upper, waterproof construction, and slip-resistant traction. Sorel comfort rated to -40degFC for extreme warmth. Removable, insulating 9 mm wool inner boot:. ~ Wool manages moisture and regulates temperature for exceptional warmth. ~ 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 to keep feet dry. Waterproof full-grain leather upper for protection and durability. Handcrafted, waterproof, vulcanized rubber shell to keep feet dry. Shaft height: 10 in. (25.4 cm). Sizing: This item runs true to size, order your normal shoe size. Calf circumference: 17 in.