Extra-fine. This sweater tank is fully fashioned in our lightweight 100% extra-fine Merino wool, a favorite for it's softness and warm-weather weight. Fitted: Slim. Sits close to the body. Responsible Wool Standard Certified: This global standard protects the sheep that supply the wool for this garment as well as the land they graze, working to make it better for the environment and the sheep. Boat neck. Straight hem.