Yixing clay teapots are made from "zisha clay," a type of clay with a high iron content produced in Yixing City. They are known for their excellent breathability and heat retention, and are said to enhance the aroma of tea. As they are used, the oil from the tea leaves permeates the clay, giving them a unique luster and texture, which is why they are also called "growing teapots." *The small one is an extra, as the details are unknown. Thank you for viewing.