In general, the cages used in deep Groove ball bearings are pressed steel ribbon cages.Pressed steel ribbon cages are generally used in the larger bearings and pressed snap cages in the smaller ones. For extra -high speed applications, synthetic - resin cages or plastic cages are used. ln recent years ,plastic snap cages which have the advantages of low torgue, long grease life and low noise are used in many kinds of miniature bearings.