The Grilamid® shell and the Carbon Reinforced Polymer CRP Cuff™ keep weight to a minimum. Our patent pending Fast Lock System™ consists of the unique Vertebra Technology™, a hardwearing ergonomic power structure that works like a backbone and the innovative Cam Closure System™, which allows for the transition from ski to walk mode in just one super-fast movement guaranteeing a perfect comfortable lockdown fit. Freedom of movement reaches exceptional levels thanks to the EZ Flex™ system incorporated into the Pebax® tongue while the shells ergonomic profile facilitates the walk mode and enhances the general level of comfort thus allowing power to be conveyed directly to the skis. The removable WarmSole™ insole creates an insulating barrier against cold and make this one of the warmest in the two-buckle category. Spitfire: The full range of La Sportiva technology applied to ski mountaineering. "