SUS304 is a kind of food-grade stainless steel with good corrosion resistance, heat resistance, low temperature strength and mechanical properties. Therefore, it is widely used to make food and beverage utensils such as thermos cups. However, although SUS304 stainless steel is safe, it is also recommended not to use the same stainless steel thermos cup for a long time, and it can be used alternately with other types of cups (such as enamel cups).