Details New! Adjustable Elastic Band System. The volume of the instep is now fully adjustable to give you the most precise fit New! Compression-molded toe box made with our Science Friction 3.0 rubber on the bottom and Xtreme Friction rubber on top Patented Concave Sole Patented 3D expandable hooking heel for a versatile fit made with climbing grade rubber Arch Flex for support and a better fit  Neutral profile that offers a wide range of motion Stretchy and breathable tongue  Our highest volume shoe High Volume version offers a wider toe box, bigger heel cup, and a boxier profile  Vegan Friendly   Technical Details Stiffness Hybrid Upper Material Syn Flex Closure Hook-and-Loop Rubber Science Friction 3.0, Xtreme Friction and Science Friction R2 Rand Midsole 1.8mm Polycarbonate Profile Neutral Asymmetrical Curvature Significant UK Sizing Upsize 1 full size to find your US size