For aspiring expert all mountain skiers the Rossignol Synergy 90 uses the sensor technology to boost energy transmission, by having the liner in direct contact with the shell. The last of 102mm mirrors the foots anatomical shape offering high performance, the total thermo fit liner is moldable around the foot and tongue areas offering maximum support and all day lasting comfort. If you want the performance from a highly tech boot but require more comfort then the Synergy 90 will work for you., while enhancing your skiing skills.