Duofold by Champion Originals 2-Layer Women's Thermal Underwear_Pink Heather_XL 2-LAYER 6-OZ. FABRIC: 100% cotton inside; 65% cotton/25% Merino wool/10% nylon outside Importado All-in-one slip comfortably smooths out all your trouble areas. 6-oz. mid-weight fabric has two non-bulky layers. Outer layer contains Merino wool for natural insulation. Inner layer is pure cotton, for softness next to your skin. Together, both layers trap air to create a warm thermal barrier.