FABRIC Yak leather GORE-TEX is a highly breathable and 100% waterproof membrane which is exceptionally thin and has over 9 billion pores per square inch. We integrate a GORE-TEX membrane into our uppers before carefully sealing them. Using this technology enables us to create comfortable shoes that are guaranteed to keep your feet dry. BIOM® NATURAL MOTION® technology is based on the natural shape and movement of the foot. It encourages the muscles and ligaments in your leg and foot to strengthen with every step — making your movements more efficient and smooth, and allowing for a more powerful push-off. BIOM’s key elements are reduced seam construction, an anatomical last which is designed to match the curves of your foot, low-to-the-ground construction, and easy flexibility. These features create an embracing glove-like fit that frees you to move with barefoot ease and efficiency.