18/8 STAINLESS STEEL INSULATED: Double wall vacuum insulation design Keep your drinks hot for 9 hours and cold for 12 hours) Premium material makes it never rust, anti - perspiration, no condensation and easy to clean. Designed for daily use and made with premium materials, our 20 oz Tumblers keep your drinks at the perfect temperature for up to 9 hours hot and 12 hours cold. This double-wall vacuum insulation ensures that your beverage will never lose its temperature and will always be free of any condensation, making it the perfect choice for any occasion. No need to worry about rust or perspiration, and cleaning is a breeze. Experience the benefits of high-quality stainless steel with our 20 oz Tumblers.