K2 Sports Men's Mach 100 Custom Fit Boa X-Training 2012 Inline Skates (Black/Orange/Silver) K2 Softboot , the original, delivers unmatched comfort with the best fit on the market The Boa closure system is fast, quick on, quick off. Boa provides custom comfort, with smooth even closure, no pressure points and allows for infinite degrees of fine tuning for the highest level of performance. Designed to feature all of the functional properties of K2's Stability Cuff with the addition of a stiff rear insert creating more support that is needed to get the most out of the bigger wheels in K2's X-Training series The Mach Hi-Lo is a revolutionary aluminum frame that utilizes an innovative 100mm/90mm. Designed to keep your weight over the balls of your feet. In other words, we put you in the proper skating position so you will skate better. It's fast, stable and th Integrating an intuition liner into a K2 Softboot enhances the comfort of the original Softboot as well as increases the performance by offering a true custom fit.