A bi-fit board is made by combining the lasting board, midsole and shank into one unified piece.
Traditionally, a lasting board is made out of a paper-like fiber that acts as the base during the lasting process (the upper is stretched down over the anatomical mold and connected to the lasting board, which then attaches to the sole). The midsole is the layer of cushion in between your insole and outsole and the shank is a small piece of support under the arch of your foot. In traditional footwear, these three units are separate pieces combined together during the lasting process. The difference in a bi-fit board is that these are all molded together into one unified piece that can't be deconstructed during the recrafting process.
Our bi-fit board unit is fabricated out of a polypropylene blend and offers a substantially lighter weight boot while still providing necessary support and flexibility.