Under Armour Heatgear Fly-By Mesh Racerback Tank - Women'sThe Under Armour Fly By Mesh Racerback Tank features a lightweight mesh fabric that delivers maximum ventilation. The smooth flatlock seams offer added comfort while 360-degree reflectivity provides extra visibility and increases safety. HeatGearŪ is best for weather between 75-100 degrees. Semi-fitted fit. 84% polyester/16% spandex. Imported.