Rubber seal: These deep groove ball bearings have double-sided rubber seal to prevent the ingress of impurities and to save lubricant. Performance: Donepart ball bearing have the advantages of low noise, fast heat dissipation, low friction, high speed and high temperature resistance. Good quality: These ball bearings are made of high quality bearing steel. Its steel construction makes it durable and resistant to deformation under heavy loads. Application: Widely used in industrial machine, motorcycle, automobile, power tools and mechanical equipment and other kinds of field. Performance ,Quiet and Cost-Effective, Double-Sealed and Pre-Lubricated, Deep Groove Ball Bearings.