Features of the La Sportiva Women's Trango Tech Leather GTX Boot Ultra-lightweight Technical mountaineering, guiding and backpacking boot Durable leather Upper with semi-automatic crampon compatibility Upper: Debossed Nubuck Leather Lining: Gore-Tex Performance Comfort Insole: 4mm Nylon/ Fiberglass Stiffener Midsole: PU Light and PU Protective Skin with Heel TPU Crampon Insert Sole: La Sportiva G?CUBEin. sole by Vibram with Impact Brake System Enhanced braking effect Enhanced traction Enhanced shock absorption Reduced articultaion fatigue Vibram is the world leader in High Performance rubber soles Multi-directional Upper hinge that allows the ankle to take advantage of its natural characteristics Upper flexes following the movement of the foot Allows for a comfortable Fit and even flex after several hours of use