The Vaporfly (top) and Alphafly (bottom) have broken myriad world records, including the marathon for both men and women. Photo by Jack Seemer for ... More interesting still: a closer look at the ...

More interesting still: a closer look at the tongue and upper reveal ACG branding — a first not just the Ultrafly but Nike’s super-shoe lineup as a whole. Of course, ACG — short for “All ...