STRETCH TO FREE YOUR STRIDE. The Nike Free RN 2018 delivers an even more adaptive fit than before. Stretch material in the upper moves with your foot, while the tri-star outsole pattern adjusts to your every step for a ride that delivers support and flexibility where you need it. Benefits • Circular-knit on the upper is made with spandex for natural movement. • Dynamic heel fit system supports from heel to ankle. • Tri-star outsole pattern adapts to your step for flexible cushioning. • Dynamic Fit technology is achieved through Flywire cables integrated with the laces for an adaptive, supportive fit. • Texture has been added under the toe and heel to enhance traction in high-abrasion zones.