On the World Cup circuit narrow boots equal precise turns and fast times. Available in a 100 flex (soft in comparison to Race FIS series boots) the RT STI features an extremely narrow 93mm last. This boot is designed to be completely custom fit by a professional boot fitter with the capabilities to bump and grind the shell to the exact fit you desire. The softer flex makes this precise fit available to junior racers, and those who may be stuck racing milder terrain thanks to their geographical location in the mid west; in both cases a softer flexing boot will allow for an increased range of motion which will make flexing the skis a much smoother process. Just like the stiffer models the RT STI 100 uses the World Cup Speed Aluminum Buckles and Dual RS 55mm strap. . Liner: Team ASY Pro Liner, Flex Rating: 100, Cuff Alignment (Y/N): Yes, Warranty: One Year, Gender: Mens, Type of Boot: Racing, Width: 93mm, Buckle Count/Type/Material: 4/WC Speed/Aluminum, Features: PU Grindable Boot Board, Skill Range: Advanced - Pro, Model Year: 2010, Product ID: 201714