The Nike Flex Experience RN 4 Running Shoe features a single-layer mesh upper with leather overlays for breathability and support. The cushioned foam midsole doubles as the outsole for comfort and durability, and flex grooves help create a natural, flexible feel. Hexagonal flex grooves let your foot move more naturally. Single-layer mesh and no-sew overlays keep the shoe supportive and light. Injected unitsole midsole doubles as the outsole for cushioning and durability. Waffle outsole pistons absorb impact and spring back for added responsiveness.