Rubber outsoles offer the optimal balance of traction and durability, with a responsive feel on unpredictable terrain.circular lug patterns provide grip during movement Removable insoles support the feet’s arches and not cause too much pressure and transfer weight over the ball of the feet. Thicker topline wrapped perfectly around feet, which make shoes not fall off during exercise Reflective strip on heel counter,make sure safty during exercise at night The purpose of minimalist shoes is to give our feet maximum amount of freedom to move and function as if we are walking barefoot. NWOT size 9(40)