Ultralight fabric traps warmth but still breathes as you run Stretch-mesh back panel for strategic ventilation 4-way stretch construction moves better in every direction Material wicks sweat & dries really fast Anti-odor technology prevents the growth of odor-causing microbes Dropped, shaped hem for enhanced coverage Reflective logos deliver greater visibility on low-light runs Ergonomically designed to solve the problem of being too cold when you start running or too hot when you get going, Under Armour's Qualifier top keep you ventilated during training. The unique hex-shaped pattern in this shirt breathes as you move, trapping a little extra warmth, but breathing as you move mile after mile. The light compression fit not only helps this ventilation but also ensures you're range of motion isn't restricted.