Named for the woman-specific double X chromosome DNA sequence, the Run XX NITRO running shoes stands behind our RUN FOR HER motto with a progressive, female-specific design. The running shoe features an updated fit that hugs a woman’s foot at the heel, instep, and arch, as well as a firmer NITRO midsole that provides cushioning over any distance. RUNGUIDE rounds things off by promoting proper alignment and increased stability. The yarn used in the upper of this PUMA x FIRST MILE version is made from post-consumer plastic waste.