The benchmark against which all others are judged, the 200 Oasis Long Sleeve Crewe is an ultra-comfortable base layer top that make the perfect foundation for cold-weather layering. Featuring icebreaker's best-selling 100% merino wool jersey fabric that’s breathable, insulating, and odor-resistant, this top also features flatlock seams throughout for a smooth next-to-skin feel. 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.