Under Armour HeatGear Flyweight Run 1/4 Zip Long Sleeve Running Top - Small - Grey Signature Moisture Transport System - The fabric actively works to wick sweat away from the skin and out of the garment, keeping you dry and cool. Mesh Ventilation - For enhanced breathability, encouraging critical airflow in high-heat areas. Athletic Cut - The garment is designed with a slimmer fit to enhance comfort and reduce bulk. HeatGear - Under Armour's technical product range. Wear this to stay light, dry and cool. Quarter-Zip - Provides ventilation when needed, and also allows for easy on-and-off.