flyrock mid gtx flyrock mid gtx ws fast hiking shoe for dynamic activities, suitable for off-road adventures where traction, protection and high cushioning are required. the vibram traction lug sole with megagrip and high cushion and high rebound eva midsole offers amazing grip and cushioning. it features dynamic fit technology that dynamically adapts the boots heel tension with your natural stride to increase comfort and stability, and the aku elica natural stride system to promote biodynamic efficiency. also available in women's version on specific female plantar anatomy.