Was my first touring boot, very comfortable, not too heavy. 10 tours on these. The K2 Mindbender 90 Alliance Alpine Touring Ski Boots are a great solution for the woman who loves skiing and doesn't want to confine her choice of terrain to what the resort offers. With a minimalist Prolite shell, super functional tour mode, and integrated tech fittings with Gripwalk soles so you can use both tech and selected alpine bindings with the same boot, the MB 90 Alliance gets the job done no matter what the venue.Last: 100 mm – An average width and volume last fits most feet.Fast Fit Entry – Softer TPU designed into the instep area of the Powerlite shell for quick and easy entry and exit.Flex: 90 – Stiff flex for intermediate to advanced women skiers.LinerLuxFit Pro Tour – Laceable, pre molded and lasted with Ultralon heat moldable foams. Features an asymmetric tongue, a medium density collar & foam package with a flex notch for increased range of motion while hiking.Shell MaterialsPowerlite Shell – The totally new Powerlite shell is purpose-built to result in the best skiing, lightest weight boots ever produced. Made with four different stiffnesses of TPU and optimized wall thickness profiling, the Powerlite shell achieves a paradoxical balance of lightweight agility and power. The resulting boots weigh in as some of the lightest alpine boots on the market, yet they ski with all the power and drive of heavier boots.Powerlock Spyne – A rear co-injected "Y" shaped supp