A ball bearing is a load bearing sphere which reduces friction in rotating loaded systems.  An example of a ball bearing would be an inline skate - a device where motion is allowed through rotation and weight is still supported by the bearing itself.

Ball bearings can be made of a variety of materials, but the most common is metal to support the load of a heavier material (i.e., a windmill)

Ball bearings are enclosed inside of a bearing system and rotate in an axial fashion upon rods or shafts that can then generate movement for a pump or plunger.

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