Women's Nike Free RN Flyknit 2017 Running Shoe Women's Nike Free RN Flyknit 2017 Running Shoe brings miles of comfort with a Flyknit constructed upper in a classic silhouette that delivers stretch and support, while the tri-star outsole pattern adjusts to your foot's every step. Flyknit constructed upper delivers stretch and support. Flywire cables provide a lightweight, locked-down fit. Auxetic outsole with Tri-star pattern enhances flexibility. Injected unit sole (IU) foam is tough enough to double as an outsole, dramatically reducing the shoe's overall weight. Heel is rounded to roll with the ground, promoting a more natural range of motion.