Duofold by Champion Originals Ankle-Length Women's Thermal-Underwear Bottoms, M-Berry Pink Heather base-layer-underwear closure 6.3-oz. 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. Tag-free elastic waistband wicks moisture for added comfort. Sleek body-sized fit, with non-chafe flat-locked seams and stretchy rib-knit cuffs. Fiber Content: "100% Cotton inside / 65% Cotton, 25% Merino wool, 10% Nylon outside"