keen women's revel iii winter boot, black/rose, 10 m us keen upper the keen revel iii walking boot is made with nubuck leather. to keep your feet warm, snug and comfortable, even in the depths of winter keen warm trapolator insulation is provided with additional bamboo charcoal material which gives 360 degrees of warmth. due to the high profile of the boot, ankle support and stability is improved increasing the protection afforded by the construction. waterproof material featured in the upper provide protection in wet and extremely cold conditions. midsole constructed from three different extra warm layers to keep the foot in constant warm and increase the protection from the cold. extremely light eva foam insulates and waterproofs the boots, further promoting comfort and dryness. outsole created from dual climate rubber to increase the grip in unpredictable conditions.