A medium-weight fabric with a unique pattern that traps heat but still breathes while you train or run. 4-Way Stretch technology allows for better movement in every direction. The material wicks away sweat and dries very quickly. Thumbholes help keep the sleeves in place and don't get in the way when not in use. The 1/4 zip allows for easy layering. Reflective details for better visibility during training in poor light. Odor control technology minimizes odor.