This 30 Oz. insulated vacuum tumbler is made of high-quality SUS 314 double wall stainless steel. 314 stainless steel Widely used in medical equipment, better than 304 stainless steel, more healthy. Your drink will maintain temperature for 24-72 hours if not days. The exterior is powder coated for a colorful and highly durable. Easy to clean, fill and drink. Even filled with ice, the bottle will not sweat. Welcome to your customization on the bottle!