2-piece stretchy, breathable Flyknit upper offers a supportive yet comfortable fit Flywire cables for enhanced lockdown through the midfoot Flex grooves on the sole enhance natural motion Flat heel for greater stability Ramp up the technology and the style in the innovative Women's Nike Free TR Flyknit 3 AMP Training Shoes. Built to meet your high performance training demands, but style-savvy enough to rock every single day, these sneakers are an essential for your active lifestyle.