These are the slippers made with a patented fabric that regulates the internal temperature to ensure the wearer's feet are always comfortable. Developed for NASA to help astronauts adapt to extreme temperature fluctuations, the fabric absorbs and stores excess body heat to prevent overheating, releasing it back to the skin as the temperature drops to keep feet warm. Also effective when worn to bed, the slippers are insulated with 3 1/2 oz. layer of fine duck down that wicks moisture away, keeping feet dry, unlike synthetic fills that tend to retain humidity. Durable cowskin soles. Machine washable. White. Women's. Fits all sizes between 7-10. (9 oz.)