Stainless Steel Classic Water Tumbler: Our stainless steel tumblers are made of double-layer stainless steel, which can keep drinks cold for 9 hours and keep warm for 3 hours. In the hot summer, our skinny tumbler can keep your drinks refreshing and make your summer fun. In cold winter days, it can also keep your coffee warm and bring you a pleasant hot drink taste. https://www.lovingbottle.com/sta...steel-water-tumbler.html