It is mainly used to prevent the leakage of lithium base grease in the inner cavity of the inner and outer spherical cages and the entry of external dust and water. The quality of the dust boot is directly related to the service life of the assembly. At present, the main materials used for dust boot are neoprene and TPE. Due to the different shape and structure of the product, the dust boot used has different structure to meet the needs of product matching.