Using levels of mesh mapped to your body, you get ventilation where you need it, plus the comfort of fewer seams. It's pretty much the most comfortable thing you'll ever train in. Soft knit fabric with engineered mesh ventilation, mapped to the places you need it most Nearly sew-free construction to eliminate chafing 4-way stretch material moves better in every direction Material wicks sweat & dries really fast Anti-odor technology prevents the growth of odor-causing microbes 360° reflective details for greater visibility on low-light runs Style #: 1361356 51% Polyester/49% Nylon Imported