The Fischer RC4 110 has a 110 flex with a 98mm last (that can mold up or down between 93mm-103mm), ideal for aggressive skiers looking for a close fitting boot. If you are a "ski fast, take chances" kind of guy, the RC4 110 will fit the bill for you. This boot features Fischer's proprietary "Vacuum Fit" System where the liner AND the shell can be completely molded to your foot/leg. This unique molding process makes for one of the most precise and comfortable boot fits on the market today. However, the RC4 110 can be skied right out of the box and will have an excellent fit regardless. The molding process will significantly improve the fit of the boot, but is not required by any means. Improve your skiing experience by slipping into the RC4 110 Vacuum. You can thank us later.