Light and fast this boot makes you feel like a wood nymph bounding through the mountains. All synthetic and designed for spider like alpine climbing performance; it is waterproof and ready for a semi-automatic crampon. The Vibram® Mulaz outsole, has an edging platform and sticky Supertrek Rubber. The 3D Flex. ankle provides supreme ankle maneuverability for technical routes. Ultralight 3-season alpine climbing boot