Perfect for all-weather light backpacking, easy to aggressive day hikes, and winter walking. Vibram Ground Control outsole is versatile for all-surface traction. BiUrethane midsole is comfortable on the heel strike, and is stable for medium loads on moderate terrain. 2.2mm nubuck upper and seamless forefoot conforms to the foot for a custom-like fit. GORE-TEX Sierra lining is waterproof and breathable. a.d.d. system allows for stability, shock absorption, and efficient propulsion. Water Shoes, Hiking Shoes, Boots.