Nike Air Zoom Structure 21 Shield Women's Running Shoe Women, Dark Sky Blue, Size. stability through rough weather made for rainy-day runs, the nike air zoom structure 21 women's running shoe features a water-repellent finish. the stability, support and responsive of nike zoom air cushioning remains. superb stability a wide, flat outsole and two types of cushioning offer stability. firmer foam cushions the arch side of the foot, while a softer foam cushions the outer side. this creates the right amount of impact protection and stability for your stride. water-repellent the one-piece flymesh fabric upper has a dwr (durable, water-repellent) finish to help keep water out. it's still lightweight and breathable to help keep your feet from overheating. breathable protection a breathable membrane lines the inside, helping block moisture while allowing air to flow. helping to keep your feet from overheating. more details reflective elements all around the shoe help you stand out forefoot nike zoom air cushioning provides a responsive, springy step flywire cables and an internal arch band provide stability that adapts to you honeycomb-shaped outsole pattern for traction weight: 255g approx. (women's size 5.5) offset: 10mm.