From New Moon:
A bit taller heel cup for extra support in a pure classic boot. Best bang for buck classic boot!
From the Manufacturer:
Challenge the competition. World Cup inspired design and a low volume fit give the X10 Classic ski boot a responsive feel and podium-worthy precision for expert and fitness oriented skiers. The classic specific design shares technology with our athlete-proven X-ium series to deliver competition level control and feel. They are insulated for warmth and protect your feet from wind and moisture.
-Precise Boot Flex, Fit
-Optimized Classic Flex