It is a kind of inert aluminum oxide ceramic balls. It is widely used in many fields, including petroleum, chemical engineering, fertilizer production, natural gas and environmental protection. It is used as covering and supporting material of catalysts in reaction vessels and as packing in towers. Having stable chemical features and a low rate of water absorption, it can resist high temperatures and high pressure. It can also resist the corrosion of acid, alkali and some other organic solvents, and are able to stand the change in temperature during the manufacturing process. The main role of these ceramic balls is to increase the distribution spots of gas or liquid, and to support and protect the activating catalyst with low strength.