Bearings allow the motor and associated parts to run smoothly, and reduces friction between moving parts. Bearings can be sealed or open. There are generally two types of bearings found in tools, ball bearings and roller bearings. Bearings wear out periodically so If you hear metal grinding or if the tool is seizing, the bearing(s) may need to be replaced.
This item fits the following models:
15-pc Thunderbolt Black Oxide Drill Bit Set
1/4" x 50 Ft Noodle Air Hose with Coupler and Plug