The product developers said we were crazy and that it couldn’t be done. We persisted - we’re stubborn like that. We kept working, kept innovating, and kept asking how can we make this ski boot work for ski mountaineers the world over that are pushing the limits of what is possible.  Born from Stratos technology, the Spectre is the no compromises result combining four-buckle downhill performance with two-buckle touring comfort and ease on the up. The shell is made of lightweight Grilamid® while the Carbon reinforced Vertebra drives the powerful 120-Flex downhill performance. The 60° range of motion and EZ Flex tongue make for an incredible walking experience and make the boot great for technical climbing. The dream has become reality; the Spectre is the best of La Sportiva innovation applied to a four buckle touring boot.

See a great review at http://coldthistle.blogspot.co.nz/2013/11/la-sportiva-spectre.html