Structure: the center of the raceway radius is on the center-line of the steel balls.
Loads: this type of bearing is mainly applied to supports radial loads

Structure: the raceway and the steel balls are angularly contacted. The center of the raceway radius deviates from the center-line of the steel balls. It needs to be installed in pairs if applied to support double direction axial load through the way of Face to Face installation (DF), Back to Back installation (DB) and Tandem installation (DT).
Loads: this type of bearing is mainly applied to support both radial load and single direction axial load.

Structure: there are two centers of the raceway radius on each side of the raceway, and both deviate from the center-line of the steel balls, which enables the Thin Section Four Point Contact Ball Bearings (X Type) to form four-point contact between the raceway and steel balls.
Loads: This type of bearing can carry radial load and axial load in double directions, which is like the back-to-back combination of paired A-Type bearings