The ultimate high-performance tele binding, the O1 has become the benchmark in reliable downhill power and control with the added bonus of resistance-free touring for uphill efficiency. Underfoot cable routing. One-piece stainless steel toe piece. Push button activation toggles between ski/tour modes. Solid wire yoke heelpiece. Three cartridge options for customizing stiffness with easy-to-read tension indicator. Standard size fits boot sole lengths 294-360 mm (fits BD boots 25 and up). Small fits boot sole lengths 265-294 mm (fits BD boots 24.5 and below).