Mons Royale Woman's Yotei BF is an ideal shirt that offers the technical performance of merino matched with an uncompromised style. It provides 100% natural warmth. The Yotei can be worn on its own or over a base layer. Made using the 100% Merino 200 material, which is warm, breathable, and odor resistant. It can be worn on its own or over a base layer.