There are two kinds of ancient lunch boxes. One is a bamboo basket, well, it seems to be called a basket box. This kind of basket is breathable and is usually used in summer, so the food is not easy to go bad. The other is made of porcelain, which is barrel-shaped and stacked layer by layer, and is called porcelain lunch box. Generally used in winter or slightly cooler weather, it has the function of heat preservation.