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. Product Details - Weight - 7oz/198g (women's size 8). Offset - 8mm (13mm/forefoot, 21mm/heel). Not intended for use as Personal Protective Equipment (PPE).