This is a genuine Fein replacement part. The groove ball bearing is designed by the manufacturer for use in power tools such as oscillating tools and rotary drills. This part is made of metal, and is generally used to allow components to spin freely. It may be found in various locations in the machine, depending on model. Please be aw...Read moreare that there are different ball bearings used in the machine. Refer to the parts diagram to be sure of ordering the correct part. You may require an Allen wrench when replacing this item. This part is sold individually.