Thrust ball bearing is separable, and designed for thrust load only.  One-way bearing can only support thrust load from one direction, and bidirectional bearing can support alternative and various thrust load from two directions. It must be given an axial precompression in work.  Its often used in principal axis of machine tool, automotive clutch, decelerator, etc. Bidirectional thrust angular contact ball bearing is used in principal axis of machine tool, and one-way thrust angular contact ball bearing is suitable for screw support.