Connecting rod “insert” or “shell” bearings reduce friction and bear the forces that are exerted by the rods as they reciprocate up and down. A thin film of oil is all that separates the bearing from the crank journals. They are designed to reduce engine component wear by embedding foreign particles trapped in pump oil into their surface. The bearing surface is hard but it is still soft enough to act as a trap to pick up some of the debris in the engine oil, which embeds in the bearing's surface, so eventually they need to be replaced.
This item fits the following models:
3-Nailer Combo Kit w/ Accessories
3-Nailer Combo Kit
1/4" x 50 Ft Noodle Air Hose with Coupler and Plug