Material: Special, breathable, handmade, top-of-the-line duan ni zisha clay from Huang Long Mine 4 and then handmade by the Siyutao workshop and stored for at least 29 years. (At Siyutao Workshop, craftsmen use ancient methods to hand-make clay, and this hand-made clay is of the highest quality). Siyutao handmade yixing clay in ancient ways (click to know more)