With X-VENT fabric technology, the 2XU Aero Long Sleeve combines a double-knit sweat-wicking body and lightweight breathable mesh back to keep you dry and cool so you can perform in comfort. Stay Cool Lightweight mesh back panel engineered to enhance breathability and ventilation. Quick-Drying Double-knit contructed main panel leverages an inner layer to transport sweat away from skin and an outer layer to disperse moisture on surface, delivering rapid moisture management. Be Seen Reflective logos and trims on front and back hem provide 360 visibility in low-light conditions.