The inbounds ripper, the Black Diamond O2 telemark binding transmits power from big boots to big skis—it's the benchmark of precision for today's aggressive skiers. Underfoot cable routing and powerful compression-spring cartridges keep the ball of your foot firmly on the ski, and as the heel rises, a progressively stiffer flex delivers power. The rear yoke features a rigid wire heelpiece, providing lateral stability and torsional support. BD's durable one-piece stainless steel toe box with a variable height toe riser withstands the abuse of hard and fast freeheel skiing. The stiffness of the O2 can be adjusted with the three different compression-spring cartridges to suit your boot flex or skiing style preference. Features: One-piece Toe Plate Progressive Active Flex Choice of 3 Spring Rates Full-coverage Skid Plate 27.5 mm Lift Specs: Standard Fits: Over 315 mm Boot Sole Length Small Fits: Under 315 mm Boot Sole Length Weight: 1.41 kg (3 lb 5 oz) MidStiff Pair Skiing Magazine: "Unchanged since last season, the O2 maintains its status as a capable, no-frills binding. With three degrees of stiffness, it accommodates powder floaters, hardpack lowriders, and mini-cliff huckers. That said, the underboot position of cable and cartridges compromise torsional rigidity on harder conditions, even with the stiffest cartridge." Backcountry magazine: ". . . this compression-spring binding utilizes under-the-foot cable routing to improve binding clearance and increase power generation. . . .For today's wider boards, this binding offers serious power. Three types of spring cartridges allow 02 skiers to find just the right flex for their ski and boot type."