The Columbia Women's Glacial IV Print Fleece Leggings are a best-selling flannel base layer bottom for women on Amazon. These leggings are made from a soft and cozy fleece fabric that provides excellent warmth and comfort. The flannel lining adds an extra layer of insulation, making them perfect for cold weather activities. The stylish print design adds a touch of flair to any outfit, making these leggings a versatile and fashionable choice.