The trainers trace their history back to 2002, when the first production samples of the Nike Free 5.0 were manufactured. Nike says it put the shoe through its paces in the research lab and found that, compared with a control group, runners using the new design showed an increase in strength and muscle growth in the foot and ankle; greater flexibility in the toes, feet and ankles; and improved overall balance. The Nike Free Flyknit Shoe is comfortable for running.Nike Free Focus Flyknit Training Shoe helps keep your foot flexing naturally throughout your workout.A Flyknit upper delivers lightweight breathability to help keep you cool. The one-piece Flyknit upper hugs your foot with a sock-like fit for incredible lightweight support.Breathable areas are seamlessly integrated in the Flyknit to provide cool comfort during your workout.The one-piece Flyknit upper hugs your foot with a sock-like fit for incredible lightweight support. About us: YourSecondShop We sell a variety of products in new, used or open box conditions. We attempt to describe every item as accurately as possible - We try to avoid surprises and give you the best possible shopping experience. ? Questions - Requests We are here for you, if you have any questions or requests, please do not hesitate to ask. We strive to answer all questions and requests as quickly as possible. ? Handling Time: We ship out Monday - Friday - Orders placed before 9AM will usually ship out that very day. ? Shipping: Very often we have the USPS Parcel selection as the chosen shipping method - we try to avoid that method at all costs - we usually have that selection to give us the most flexibility for us to chose either USPS Priority, FEDEX or UPS - all those options are are never longer than Parcel Select. Is your location excluded? Want your item shipped with a certain carrier? Just ask us - there's a good chance we can accommodate your request. ??? Returns: Products are returnable as long as the listing says returns accepted. Returns are free if the product is damaged, or not as described. ? Feedback: We of course only want positive feedback - so before you post anything negative please try working it out with us. We are here to give you the most wonderful shopping experience! YourSecondShop