A-ZX is a series of 26 collaborations with sneaker boutiques and sneaker lovers across the globe. We worked with each to create riffs on shoes from the ZX series, the first adidas running franchise. C is for Concepts, a Boston stronghold. They were the natural choice to work with on a Boston Marathon® tribute shoe. The metallic silver foil upper and reflective laces nod to the heat blankets that athletes use at the finish line.