Mountain boots with uppers made from stiff materials can restrict the natural articulation of the ankle joint causing discomfort when walking and restricting the freedom of movement when climbing. 

Bi-Flex eliminates this problem by carefully positioning panels of soft pliable materials in specific areas of the upper. These soft compressible panels act like hinges to allow the natural articulation of the ankle in both the lateral and fore/aft directions. Hard incompressible components such as lace eyelets are either made from soft textile materials instead or repositioned so as to not cause pressure points or impede articulation. Bi-Flex greatly enhancing the ergonomics and comfort of high ankle mountain boots.

Ankle Articulation System.

Bi-Flex is a system developed to improve the ergonomic articulation of the ankle area on mountain boots.