Adaptive Fit Last 102mm-104mm: The Adaptive Fit boots essentially have two lasts, one at 102mm and one at 104mm * 80/90 Flex Rating: This boot has a flex rating in the intermediate to advanced range, and can be adjusted between the two settings. * Replaceable Toe and Heel Pads: This is a must-have for skiers that don"t live in ski in/ski out condos. * HeatFit/High Performance HeatFit Liner: Self molding inserts in the liner and tongue quickly adapt to the shape of your feet, just by wearing and skiing them. * Spine-Tech Buckles: The Spine-Tech buckle features a closure point that stays in place (it looks like a spinal cord)