This is the original Nike Alphafly racing shoe designed for marathon racing, and really any road racing distance. This version of the shoe is what Eliud Kipchoge used when he ran sub 2:00 in the marathon. I used this pair for one 5 mile race and then one 15 mile training run. They just didn’t fit my feet the way I wanted, but I held onto them for too long. Many Nike pro athletes still use this version over the newer models.