The Nike Air Span 4+ is made for the runner that looks for a light, breathable and stable running shoe featuring Nike+ technology. Minimal, very open and breathable sandwich mesh upper. Thin and flexible overlays add support and great toe off. New last offers better fit. Encapsulated flexible Air-Sole® unit in the heel and forefoot provides cushioning. Lateral soft crash pad and dual-density posting medially helps prevent overpronation. Sticky rubber Waffle® and Duralon™ in the forefoot. BRS 1000™ gives great traction, cushioning and durability in the heel. Natural motion flexgrooves. Wt. 11.2 oz.