C.A.S. Technology allows full customization of the liner and shell, ensuring a personalized fit for exceptional support, precision, and all-day comfort on the slopes; T-Drive Technology creates a stronger and more effective connection between the cuff and the shell, that supports the boot flex and avoids plastic deformation; Utilizes softer plastic over the instep area that allows the shell to open easier as you are entering or exiting the boot; Innovative Lift Lock system holds the buckles up and out of the way so they don't catch while getting in or out of your boots; Gripwalk soles deliver superior walking comfort and grip on slippery surfaces; Medium Volume (100mm) is perfect for skiers with medium foot's sole or for those who prefer a regular fit; Medium Flex (110) is for intermediate and/or medium-sized skiers