Ventilated mesh panels positioned across the back and under the arms allow the Under Armour HeatGear Flyweight Run Short Sleeve Running T-Shirt to breathe and thereby regulate the wearer's temperature, particularly across these critical heat zones. Under Armour's signature Moisture Transport System wicks sweat away from the body to encourage a cooler, drier environment, whilst anti-odour technology eradicates odour carrying bacteria before it has a chance to spread. Reflective components preserve the wearer's visibility in diminished light.