A heavyweight base layer top with body-mapped ventilation for highly aerobic days in cold weather, the 260 Zone Long Sleeve Half Zip is warm, odor-resistant, and incredibly breathable. The Zone’s body-mapping technology combines a merino wool and LYCRA blend with strategically zoned panels of eyelet merino mesh that actively controls temperature. The half-zip design allows for easy layering and additional heat dumping. Underarm gussets and raglan sleeves increase range of motion, and the flatlock seams reduce chafing. Inspired by nature, icebreaker harnesses the performance qualities of natural fibers to offer an alternative to clothing based on petrochemical synthetics. Merino is an annually renewable fiber that naturally resists odors, keeps you cool when it’s hot and warm when it’s not, and lets your skin breathe for comfort all day, every day.