Ball Bearing PU Polyurethane Flat Type Inner Diameter 6mm 8mm 10mm Rubber Coated Bearings. Noise Reduction Design: Rubber coating provides low voice performance and wear resistance. Corrosion Prevention: Special rubber layer ensures stable operation in harsh environments. Customizable Inner Diameter: Available in 5mm, 6mm, 8mm, and 10mm inner diameters. High Precision Rating: Features P6 precision rating for machine tool applications. OEM/ODM Service: Supports OEM and ODM services with dedicated R&D engineers.