The Double-Insulated Mountaineer is an excellent choice for the outdoorsman needing a warmer boot for the most frigid conditions. This is the warmest boot Hoffman makes! This boot comes with a removable 9mm wool felt liner, and the waterproof rubber bottom is insulated with 200g of Thinsulate. The rebuildable, crack-resistant rubber bottom features a steel shank for arch support. Hoffman's air-grip sole provides excellent traction. Their premium contour leather uppers are made with their 7.5 oz. premium oil tanned leather.