Vibram XSV rubber outsole. Offset asymmetrical toe box places power and energy under the big toe, creating an inside-edge sweet spot. Slip-lasted construction. * 1.1 mm Laspoflex midsole (forefoot only). Dynamic slingshot heel band that focuses power to the toe box. On sizing, please note climbing shoe sizes are only a suggestion as fit is highly personal; foot shape, use, and style all play into size selection.