As the name suggests, hybrid ceramic bearings sit between traditional steel bearings and full ceramic options. The inner and outer rings of hybrid bearings are made of steel, whereas the rolling elements of the bearing are made of a ceramic material, usually silicon nitride. They are used for low friction applications due to their greater ability to cope with very limited lubrication. They can be run unlubricated but speeds should be kept low.
As the silicon nitride balls are much lighter than steel, hybrid bearings are also popular for high speed applications provided an appropriate high speed lubricant is used.