NIKE Free 4.0 V3 Womens Running Shoes 580406-333 Synthetic Synthetic and mesh upper Textured mesh full inner sleeve for a dynamic, sock-like fit that hugs the foot Waffle outsole pistons for greater traction and durability and a more efficient toe-off Abrasion-resistant rubber under high-wear areas for enhanced durability Diagonal cuts through the arch to encourage natural motion flexibility and help increase foot stren