engineered for cold-weather performance. built with COOLmatic | EXP DIAMAfleece lite™, a lightweight fabric we developed with our Japanese mill, this long sleeve features a smooth outer surface and a soft brushed diamond grid on the inside for comfort. embedded with carbon yarn, it enhances temperature regulation and odor control, making it the ideal layered with our HLSTShirt for chilly runs or a standalone piece on milder days. lightweight, breathable, and versatile – designed to keep you moving through the cold.