NIKE WMNS FREE WALK+ (WOMENS) Synthetic Perforated synthetic leather overlays for support and breathability Flex grooves for flexibility and a naturally efficient footstrike A soft, flexible midsole layer fused to the outsole for low-profile cushioning Rubber inserts on the outsole for enhanced durability in high-wear zones Made to mimic the movement of bare feet, the flex grooves that run down the length and width of the womens Free Walk enhance the shoe's natural feel and flexibility