Warm. Black technology silk patch thermal underwear, which integrates warmth, skin beauty and slimming, eliminates the need to wear bulky sweaters and down jackets in winter, and it is easy to spend the winter with a coat and a thermal suit. This thermal underwear adopts double thermal insulation design, the outer layer is velvet, and the inner layer is silk thermal insulation patch, which has double thermal storage guarantee and can be heated at constant temperature for 24 hours, and will not freeze at MINUS 20℃.