Authentic Nike product purchased from an authorized retailer. Size is 27.5, and the knit material provides a good fit. I've run 90 kilometers in these, including two half marathons, but they don't suit my feet, so I'm selling them. There's a small gap, so I've done a minor repair on the right toe area, but it's not noticeable. The original insoles are not included as I replaced them with my own. (I struggled to remove them due to the adhesive and couldn't reuse them, so I discarded them.) The box is not included, but I will provide the original shoe bag if you'd like. These are used items, so I hope to have a pleasant transaction with someone who understands this. Thank you. #NIKE Alphafly 3 Gender: Men's Use: Long Distance/Marathon Shoe Height: Low Cut