The S/Lab X-Alp Ski Boot is an ultralight alpine touring boot straight out of Salomon's lab of gram-counting ski geeks who found out that a good ski boot doesn't necessarily need a tongue or full cuff to ski well. Salomon achieved this tongue-less design by adding carbon to the cuff and making the spine completely out of carbon. As a result, the X-Alp checks in around two pounds per boot, and this model is the stiffest option available in the X-Alp series, making this boot a great choice for backcountry skiers who want to tour far and still have a decent downhill ride.