High precision thin wall bearing rings, very quiet and very strong bearing capacity. These ball bearings are three design, and extremely small, most of the cross section is square. In these series, even the larger diameter shaft and the bearing hole, the cross section is unchanged. These bearings and other so called cross-section (CS). It is this characteristic of the standard series ISO thin wall bearing and conventional bearing rings to distinguish. 

Thus, the larger cross section can be selected and used more carrying capacity without changing the bearing shaft diameter. Thin-walled bearing rings can be designed to require very little space is extremely light and bearings.