The Perfect Running Shirt The Under Armour HeatGear® Flyweight Tee for Women is lightweight and breathable. Experience the lightweight composition of this shirt and enjoy the carefree sensation of absolute dryness and comfort. This is your perfect running shirt, and it will surely exceed your expectations! Technology The HeatGear® Flyweight Tee wicks sweat away from your skin, making you comfortable and dry. The HeatGear® fabric is UPF 50 and blocks 97% of UV rays, reducing the risk of skin damage and premature skin aging. For optimal visibility, it features 360 degree reflectors which also reflect the style of this shirt. PolyArmour® holds moisture and dries quickly, regulating the temperature. The ergonomic flatlock seams feel smooth on the skin, and do not rub or cause irritation.