We flattened out the fibers and added some science to create a game-changing fabric that quickly pulls heat away from the skin-keeping you calm, cool, and crushing at max capacity. Ultra-light stretch woven outer fabric with interior mesh lining is durable & breathable. Iso-Chill sweatband helps disperse body heat, making it feel cool to the touch. Laser perforations for added ventilation where you need it. Adjustable snapback closure. Reflective logo & details for added visibility on low-light runs, UA Free Fit: unstructured front conforms to your head for a sleek, low profile fit. 100% Polyester.