Heading out in very cold weather? Wear these thermal-underwear bottoms to stay warm during low-impact exercise. 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. Stretchy tag-free waistband wicks moisture for added comfort. Sleek feminine fit, with non-chafe flat-locked seams. Ankle length for cozy coverage.