Double-knit fabric is soft, stretchy and warm for excellent comfort and mobility. The material wicks away sweat and dries very quickly. 4-Way Stretch technology allows for better movement in every direction. UPF 50+ protects the skin from the sun's harmful rays. Secure zippered chest pocket for storing keys or credit cards during long runs. A large 1/2 zip allows for easy layering, and side vents add breathability. 360° reflectivity for better visibility when running in low light. Odor control technology minimizes odor.