The inner lining is made from 100% cotton for comfort, with an extra layer of HEATTECH for warmth all the way down to the ankles. HEATTECH has features such as heat retention, heat generation, moisture wicking, and antibacterial/odor prevention. Stretchy, soft fabric with excellent shape retention. A warm layer with brushed 100% cotton on the inner side. Full length leggings that are warm down to the ankles.