The Nike Free RN 2017 is a perfect choice for interval training and long-distance runs, just like its predecessor. Its flexible design enables smooth and natural movements. The 'Black Anthracite' version boasts a circular seamless mesh upper that provides excellent breathability and durability, thanks to the reinforced zones. The integrated tongue adds to the seamless fit, while the Flywire cables connected to the sole unit offer reliable support. Upon ground-strike, the dual-layer midsole expands and contracts, allowing your foot to flex naturally. Contributing to the shoe's flexibility is the tri-star outsole, designed to provide optimal traction and grip.