NIKE Lady Flex Run 2012 Running Shoes Synthetic Breathable mesh upper - For breathability and a comfortable fit. Phylon Midsole - For low-profile and lightweight cushioning Fused Phylite Midsole and Outsole - This ultra-lightweight material provide an extremely smooth and resilient ride giving you a comfortable running experience. Flex Grooves - For enhanced flexibility and a smooth, efficient stride. Midfoot Strap - Attaches to the laces for a secure, comfortable fit.