Born for the steep spines of the Chugach, the Custom is the stiffest tele boot Black Diamond makes. Warning: The combination of alpine overlap construction and Triax-Pro Frame (with Flex 130 rating) makes the Custom a stiff mofo that demands aggressive skier input. Additionally, the RidStiff bellows offers a very stiff yet responsive flex. The thermoformable foot bed and Power Fit Liner ensure a deluxe fit that’ll keep you on the mountain and charging. Not compatible with three-pin bindings.