Two-layer fabric with an extra warm, brushed inner side and a smooth, quick-drying exterior. ColdGear infrared technology uses a soft heat-conducting coating to absorb and retain body heat. The material drains sweat away and dries very quickly. 4-Way Stretch technology allows for better movement in every direction. Practical front 1/2 zipper for easier on/off. Reflective details for running in low light.