The Nike Wmns Free RN 2018 'Black' shoe is designed to enhance both short-term running and sprinting capabilities by incorporating flexible technology. Its circular-knit upper is made with spandex and reinforced by integrated Flywire cables within the lacing system. This sneaker features a rounded heel that is strengthened by a wide strap and padding. Additionally, its lightweight foam sole allows for natural range of motion as it expands and contracts with the foot.