Miniature and instrument ball bearings can be divided into two basic types, deep groove and angular contact. The first (deep groove) can be further divided into the following five classes depending on their design details:
Standard type
Flanged outer ring
Extended inner ring
Expanded type in which one ring has a radial thickness that is larger than normal compared with the bearing width.
Thin section type in which both rings are extra thin in the radial direction.
